diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 000000000000..3d5e08e47d1d
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,5 @@
+# Mark generated protobuf files to be collapsed by default in PRs
+# See: https://github.com/github/linguist/#generated-code
+*_pb2.py         linguist-generated=true
+*_pb2.pyi        linguist-generated=true
+
diff --git a/cirq/__init__.py b/cirq/__init__.py
index 6e0275a11689..b67357c84d03 100644
--- a/cirq/__init__.py
+++ b/cirq/__init__.py
@@ -117,6 +117,7 @@
     bidiagonalize_unitary_with_special_orthogonals,
     block_diag,
     CONTROL_TAG,
+    deconstruct_single_qubit_matrix_into_angles,
     diagonalize_real_symmetric_and_sorted_diagonal_matrices,
     diagonalize_real_symmetric_matrix,
     dot,
@@ -139,6 +140,7 @@
     kron_with_controls,
     map_eigenvalues,
     match_global_phase,
+    matrix_commutes,
     matrix_from_basis_coefficients,
     partial_trace,
     partial_trace_of_state_vector_as_mixture,
@@ -315,6 +317,7 @@
     STATE_VECTOR_LIKE,
     to_valid_density_matrix,
     to_valid_state_vector,
+    validate_indices,
     validate_normalized_state,
     validate_normalized_state_vector,
     validate_qid_shape,
@@ -379,6 +382,7 @@
     Sweepable,
     to_resolvers,
     to_sweep,
+    to_sweeps,
     TrialResult,
     UnitSweep,
     Zip,
@@ -479,6 +483,7 @@
     to_json,
     obj_to_dict_helper,
     trace_distance_bound,
+    trace_distance_from_angle_list,
     unitary,
     validate_mixture,
 )
diff --git a/cirq/google/api/v1/operations_pb2.py b/cirq/google/api/v1/operations_pb2.py
index 34c8d2f22e87..d178d03ebcc1 100644
--- a/cirq/google/api/v1/operations_pb2.py
+++ b/cirq/google/api/v1/operations_pb2.py
@@ -379,53 +379,53 @@
 DESCRIPTOR.message_types_by_name['Operation'] = _OPERATION
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-Qubit = _reflection.GeneratedProtocolMessageType('Qubit', (_message.Message,), dict(
-  DESCRIPTOR = _QUBIT,
-  __module__ = 'cirq.google.api.v1.operations_pb2'
+Qubit = _reflection.GeneratedProtocolMessageType('Qubit', (_message.Message,), {
+  'DESCRIPTOR' : _QUBIT,
+  '__module__' : 'cirq.google.api.v1.operations_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Qubit)
-  ))
+  })
 _sym_db.RegisterMessage(Qubit)
 
-ParameterizedFloat = _reflection.GeneratedProtocolMessageType('ParameterizedFloat', (_message.Message,), dict(
-  DESCRIPTOR = _PARAMETERIZEDFLOAT,
-  __module__ = 'cirq.google.api.v1.operations_pb2'
+ParameterizedFloat = _reflection.GeneratedProtocolMessageType('ParameterizedFloat', (_message.Message,), {
+  'DESCRIPTOR' : _PARAMETERIZEDFLOAT,
+  '__module__' : 'cirq.google.api.v1.operations_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ParameterizedFloat)
-  ))
+  })
 _sym_db.RegisterMessage(ParameterizedFloat)
 
-ExpW = _reflection.GeneratedProtocolMessageType('ExpW', (_message.Message,), dict(
-  DESCRIPTOR = _EXPW,
-  __module__ = 'cirq.google.api.v1.operations_pb2'
+ExpW = _reflection.GeneratedProtocolMessageType('ExpW', (_message.Message,), {
+  'DESCRIPTOR' : _EXPW,
+  '__module__' : 'cirq.google.api.v1.operations_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ExpW)
-  ))
+  })
 _sym_db.RegisterMessage(ExpW)
 
-ExpZ = _reflection.GeneratedProtocolMessageType('ExpZ', (_message.Message,), dict(
-  DESCRIPTOR = _EXPZ,
-  __module__ = 'cirq.google.api.v1.operations_pb2'
+ExpZ = _reflection.GeneratedProtocolMessageType('ExpZ', (_message.Message,), {
+  'DESCRIPTOR' : _EXPZ,
+  '__module__' : 'cirq.google.api.v1.operations_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ExpZ)
-  ))
+  })
 _sym_db.RegisterMessage(ExpZ)
 
-Exp11 = _reflection.GeneratedProtocolMessageType('Exp11', (_message.Message,), dict(
-  DESCRIPTOR = _EXP11,
-  __module__ = 'cirq.google.api.v1.operations_pb2'
+Exp11 = _reflection.GeneratedProtocolMessageType('Exp11', (_message.Message,), {
+  'DESCRIPTOR' : _EXP11,
+  '__module__' : 'cirq.google.api.v1.operations_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Exp11)
-  ))
+  })
 _sym_db.RegisterMessage(Exp11)
 
-Measurement = _reflection.GeneratedProtocolMessageType('Measurement', (_message.Message,), dict(
-  DESCRIPTOR = _MEASUREMENT,
-  __module__ = 'cirq.google.api.v1.operations_pb2'
+Measurement = _reflection.GeneratedProtocolMessageType('Measurement', (_message.Message,), {
+  'DESCRIPTOR' : _MEASUREMENT,
+  '__module__' : 'cirq.google.api.v1.operations_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Measurement)
-  ))
+  })
 _sym_db.RegisterMessage(Measurement)
 
-Operation = _reflection.GeneratedProtocolMessageType('Operation', (_message.Message,), dict(
-  DESCRIPTOR = _OPERATION,
-  __module__ = 'cirq.google.api.v1.operations_pb2'
+Operation = _reflection.GeneratedProtocolMessageType('Operation', (_message.Message,), {
+  'DESCRIPTOR' : _OPERATION,
+  '__module__' : 'cirq.google.api.v1.operations_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Operation)
-  ))
+  })
 _sym_db.RegisterMessage(Operation)
 
 
diff --git a/cirq/google/api/v1/params_pb2.py b/cirq/google/api/v1/params_pb2.py
index c97b5e0a0eb7..53fe31970461 100644
--- a/cirq/google/api/v1/params_pb2.py
+++ b/cirq/google/api/v1/params_pb2.py
@@ -339,60 +339,60 @@
 DESCRIPTOR.message_types_by_name['ParameterDict'] = _PARAMETERDICT
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-ParameterSweep = _reflection.GeneratedProtocolMessageType('ParameterSweep', (_message.Message,), dict(
-  DESCRIPTOR = _PARAMETERSWEEP,
-  __module__ = 'cirq.google.api.v1.params_pb2'
+ParameterSweep = _reflection.GeneratedProtocolMessageType('ParameterSweep', (_message.Message,), {
+  'DESCRIPTOR' : _PARAMETERSWEEP,
+  '__module__' : 'cirq.google.api.v1.params_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ParameterSweep)
-  ))
+  })
 _sym_db.RegisterMessage(ParameterSweep)
 
-ProductSweep = _reflection.GeneratedProtocolMessageType('ProductSweep', (_message.Message,), dict(
-  DESCRIPTOR = _PRODUCTSWEEP,
-  __module__ = 'cirq.google.api.v1.params_pb2'
+ProductSweep = _reflection.GeneratedProtocolMessageType('ProductSweep', (_message.Message,), {
+  'DESCRIPTOR' : _PRODUCTSWEEP,
+  '__module__' : 'cirq.google.api.v1.params_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ProductSweep)
-  ))
+  })
 _sym_db.RegisterMessage(ProductSweep)
 
-ZipSweep = _reflection.GeneratedProtocolMessageType('ZipSweep', (_message.Message,), dict(
-  DESCRIPTOR = _ZIPSWEEP,
-  __module__ = 'cirq.google.api.v1.params_pb2'
+ZipSweep = _reflection.GeneratedProtocolMessageType('ZipSweep', (_message.Message,), {
+  'DESCRIPTOR' : _ZIPSWEEP,
+  '__module__' : 'cirq.google.api.v1.params_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ZipSweep)
-  ))
+  })
 _sym_db.RegisterMessage(ZipSweep)
 
-SingleSweep = _reflection.GeneratedProtocolMessageType('SingleSweep', (_message.Message,), dict(
-  DESCRIPTOR = _SINGLESWEEP,
-  __module__ = 'cirq.google.api.v1.params_pb2'
+SingleSweep = _reflection.GeneratedProtocolMessageType('SingleSweep', (_message.Message,), {
+  'DESCRIPTOR' : _SINGLESWEEP,
+  '__module__' : 'cirq.google.api.v1.params_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.SingleSweep)
-  ))
+  })
 _sym_db.RegisterMessage(SingleSweep)
 
-Points = _reflection.GeneratedProtocolMessageType('Points', (_message.Message,), dict(
-  DESCRIPTOR = _POINTS,
-  __module__ = 'cirq.google.api.v1.params_pb2'
+Points = _reflection.GeneratedProtocolMessageType('Points', (_message.Message,), {
+  'DESCRIPTOR' : _POINTS,
+  '__module__' : 'cirq.google.api.v1.params_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Points)
-  ))
+  })
 _sym_db.RegisterMessage(Points)
 
-Linspace = _reflection.GeneratedProtocolMessageType('Linspace', (_message.Message,), dict(
-  DESCRIPTOR = _LINSPACE,
-  __module__ = 'cirq.google.api.v1.params_pb2'
+Linspace = _reflection.GeneratedProtocolMessageType('Linspace', (_message.Message,), {
+  'DESCRIPTOR' : _LINSPACE,
+  '__module__' : 'cirq.google.api.v1.params_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Linspace)
-  ))
+  })
 _sym_db.RegisterMessage(Linspace)
 
-ParameterDict = _reflection.GeneratedProtocolMessageType('ParameterDict', (_message.Message,), dict(
+ParameterDict = _reflection.GeneratedProtocolMessageType('ParameterDict', (_message.Message,), {
 
-  AssignmentsEntry = _reflection.GeneratedProtocolMessageType('AssignmentsEntry', (_message.Message,), dict(
-    DESCRIPTOR = _PARAMETERDICT_ASSIGNMENTSENTRY,
-    __module__ = 'cirq.google.api.v1.params_pb2'
+  'AssignmentsEntry' : _reflection.GeneratedProtocolMessageType('AssignmentsEntry', (_message.Message,), {
+    'DESCRIPTOR' : _PARAMETERDICT_ASSIGNMENTSENTRY,
+    '__module__' : 'cirq.google.api.v1.params_pb2'
     # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ParameterDict.AssignmentsEntry)
-    ))
+    })
   ,
-  DESCRIPTOR = _PARAMETERDICT,
-  __module__ = 'cirq.google.api.v1.params_pb2'
+  'DESCRIPTOR' : _PARAMETERDICT,
+  '__module__' : 'cirq.google.api.v1.params_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ParameterDict)
-  ))
+  })
 _sym_db.RegisterMessage(ParameterDict)
 _sym_db.RegisterMessage(ParameterDict.AssignmentsEntry)
 
diff --git a/cirq/google/api/v1/program_pb2.py b/cirq/google/api/v1/program_pb2.py
index e20e967b08e0..c59833be3a07 100644
--- a/cirq/google/api/v1/program_pb2.py
+++ b/cirq/google/api/v1/program_pb2.py
@@ -265,46 +265,46 @@
 DESCRIPTOR.message_types_by_name['Result'] = _RESULT
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-Program = _reflection.GeneratedProtocolMessageType('Program', (_message.Message,), dict(
-  DESCRIPTOR = _PROGRAM,
-  __module__ = 'cirq.google.api.v1.program_pb2'
+Program = _reflection.GeneratedProtocolMessageType('Program', (_message.Message,), {
+  'DESCRIPTOR' : _PROGRAM,
+  '__module__' : 'cirq.google.api.v1.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Program)
-  ))
+  })
 _sym_db.RegisterMessage(Program)
 
-RunContext = _reflection.GeneratedProtocolMessageType('RunContext', (_message.Message,), dict(
-  DESCRIPTOR = _RUNCONTEXT,
-  __module__ = 'cirq.google.api.v1.program_pb2'
+RunContext = _reflection.GeneratedProtocolMessageType('RunContext', (_message.Message,), {
+  'DESCRIPTOR' : _RUNCONTEXT,
+  '__module__' : 'cirq.google.api.v1.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.RunContext)
-  ))
+  })
 _sym_db.RegisterMessage(RunContext)
 
-ParameterizedResult = _reflection.GeneratedProtocolMessageType('ParameterizedResult', (_message.Message,), dict(
-  DESCRIPTOR = _PARAMETERIZEDRESULT,
-  __module__ = 'cirq.google.api.v1.program_pb2'
+ParameterizedResult = _reflection.GeneratedProtocolMessageType('ParameterizedResult', (_message.Message,), {
+  'DESCRIPTOR' : _PARAMETERIZEDRESULT,
+  '__module__' : 'cirq.google.api.v1.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.ParameterizedResult)
-  ))
+  })
 _sym_db.RegisterMessage(ParameterizedResult)
 
-MeasurementKey = _reflection.GeneratedProtocolMessageType('MeasurementKey', (_message.Message,), dict(
-  DESCRIPTOR = _MEASUREMENTKEY,
-  __module__ = 'cirq.google.api.v1.program_pb2'
+MeasurementKey = _reflection.GeneratedProtocolMessageType('MeasurementKey', (_message.Message,), {
+  'DESCRIPTOR' : _MEASUREMENTKEY,
+  '__module__' : 'cirq.google.api.v1.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.MeasurementKey)
-  ))
+  })
 _sym_db.RegisterMessage(MeasurementKey)
 
-SweepResult = _reflection.GeneratedProtocolMessageType('SweepResult', (_message.Message,), dict(
-  DESCRIPTOR = _SWEEPRESULT,
-  __module__ = 'cirq.google.api.v1.program_pb2'
+SweepResult = _reflection.GeneratedProtocolMessageType('SweepResult', (_message.Message,), {
+  'DESCRIPTOR' : _SWEEPRESULT,
+  '__module__' : 'cirq.google.api.v1.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.SweepResult)
-  ))
+  })
 _sym_db.RegisterMessage(SweepResult)
 
-Result = _reflection.GeneratedProtocolMessageType('Result', (_message.Message,), dict(
-  DESCRIPTOR = _RESULT,
-  __module__ = 'cirq.google.api.v1.program_pb2'
+Result = _reflection.GeneratedProtocolMessageType('Result', (_message.Message,), {
+  'DESCRIPTOR' : _RESULT,
+  '__module__' : 'cirq.google.api.v1.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v1.Result)
-  ))
+  })
 _sym_db.RegisterMessage(Result)
 
 
diff --git a/cirq/google/api/v2/BUILD b/cirq/google/api/v2/BUILD
index eed752f5fd9e..253249524880 100644
--- a/cirq/google/api/v2/BUILD
+++ b/cirq/google/api/v2/BUILD
@@ -2,6 +2,33 @@ package(default_visibility = ["//visibility:public"])
 
 load("@com_google_protobuf//:protobuf.bzl", "py_proto_library")
 
+proto_library(
+    name = "batch_proto",
+    srcs = ["batch.proto"],
+    deps = [
+        ":program_proto",
+        ":result_proto",
+        ":run_context_proto"
+    ],
+)
+
+py_proto_library(
+    name = "batch_py_proto",
+    srcs = ["batch.proto"],
+    deps = [
+        ":program_py_proto",
+        ":result_py_proto",
+        ":run_context_py_proto"
+    ],
+)
+
+cc_proto_library(
+    name = "batch_cc_proto",
+    deps = [
+        ":batch_proto"
+    ],
+)
+
 proto_library(
     name = "device_proto",
     srcs = ["device.proto"],
diff --git a/cirq/google/api/v2/batch.proto b/cirq/google/api/v2/batch.proto
new file mode 100644
index 000000000000..d338a5238dc9
--- /dev/null
+++ b/cirq/google/api/v2/batch.proto
@@ -0,0 +1,58 @@
+syntax = "proto3";
+
+import "cirq/google/api/v2/program.proto";
+import "cirq/google/api/v2/result.proto";
+import "cirq/google/api/v2/run_context.proto";
+
+package cirq.google.api.v2;
+
+option java_package = "com.google.cirq.google.api.v2";
+option java_outer_classname = "BatchProto";
+option java_multiple_files = true;
+
+// A Batch of multiple circuits that should be run together
+// as one QuantumProgram within Quantum Engine.
+//
+// Note: Batching is done on a best-effort basis.
+// Circuits will be be bundled together, but the size
+// of the total batch and different hardware constraints may
+// cause the programs to be executed seperately on the hardware.
+message BatchProgram {
+
+  // The circuits that should be bundled together as one program
+  repeated Program programs = 1;
+}
+
+// A batch of contexts for running a bundled batch of programs
+// To be used in conjunction with BatchProgram
+message BatchRunContext {
+
+  // Run contexts for each program in the BatchProgram
+  // Each RunContext should map directly to a Program in the corresponding
+  // BatchProgram.
+  //
+  // This message must have one RunContext for each Program in the
+  // BatchProgram, and the order of the RunContext messages should
+  // match the order of the Programs in the BatchProgram.
+  repeated RunContext run_contexts = 1;
+}
+
+
+// The result returned from running a BatchProgram/BatchRunContext
+message BatchResult {
+
+  // Results returned from executing a BatchProgram/BatchRunContext pair.
+  //
+  // After a BatchProgram and BatchRunContext is successfully run in
+  // Quantum Engine, the expected result if successful will be a BatchResult.
+  //
+  // Each Result in this message will directly correspond to a Program/
+  // RunContext pair in the request.  There will be one Result in this message
+  // for each corresponding pair in the request and the order of the Results
+  // will match the order of the Programs from the request.
+  //
+  // In case of partial results, an empty (default) Result object will be
+  // populated for programs that were not able to be run correctly.
+  repeated Result results = 1;
+}
+
diff --git a/cirq/google/api/v2/device_pb2.py b/cirq/google/api/v2/device_pb2.py
index 828fa4b31ea9..c286442dc2da 100644
--- a/cirq/google/api/v2/device_pb2.py
+++ b/cirq/google/api/v2/device_pb2.py
@@ -414,53 +414,53 @@
 DESCRIPTOR.message_types_by_name['Target'] = _TARGET
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-DeviceSpecification = _reflection.GeneratedProtocolMessageType('DeviceSpecification', (_message.Message,), dict(
-  DESCRIPTOR = _DEVICESPECIFICATION,
-  __module__ = 'cirq.google.api.v2.device_pb2'
+DeviceSpecification = _reflection.GeneratedProtocolMessageType('DeviceSpecification', (_message.Message,), {
+  'DESCRIPTOR' : _DEVICESPECIFICATION,
+  '__module__' : 'cirq.google.api.v2.device_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.DeviceSpecification)
-  ))
+  })
 _sym_db.RegisterMessage(DeviceSpecification)
 
-GateSet = _reflection.GeneratedProtocolMessageType('GateSet', (_message.Message,), dict(
-  DESCRIPTOR = _GATESET,
-  __module__ = 'cirq.google.api.v2.device_pb2'
+GateSet = _reflection.GeneratedProtocolMessageType('GateSet', (_message.Message,), {
+  'DESCRIPTOR' : _GATESET,
+  '__module__' : 'cirq.google.api.v2.device_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.GateSet)
-  ))
+  })
 _sym_db.RegisterMessage(GateSet)
 
-GateDefinition = _reflection.GeneratedProtocolMessageType('GateDefinition', (_message.Message,), dict(
-  DESCRIPTOR = _GATEDEFINITION,
-  __module__ = 'cirq.google.api.v2.device_pb2'
+GateDefinition = _reflection.GeneratedProtocolMessageType('GateDefinition', (_message.Message,), {
+  'DESCRIPTOR' : _GATEDEFINITION,
+  '__module__' : 'cirq.google.api.v2.device_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.GateDefinition)
-  ))
+  })
 _sym_db.RegisterMessage(GateDefinition)
 
-ArgDefinition = _reflection.GeneratedProtocolMessageType('ArgDefinition', (_message.Message,), dict(
-  DESCRIPTOR = _ARGDEFINITION,
-  __module__ = 'cirq.google.api.v2.device_pb2'
+ArgDefinition = _reflection.GeneratedProtocolMessageType('ArgDefinition', (_message.Message,), {
+  'DESCRIPTOR' : _ARGDEFINITION,
+  '__module__' : 'cirq.google.api.v2.device_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ArgDefinition)
-  ))
+  })
 _sym_db.RegisterMessage(ArgDefinition)
 
-ArgumentRange = _reflection.GeneratedProtocolMessageType('ArgumentRange', (_message.Message,), dict(
-  DESCRIPTOR = _ARGUMENTRANGE,
-  __module__ = 'cirq.google.api.v2.device_pb2'
+ArgumentRange = _reflection.GeneratedProtocolMessageType('ArgumentRange', (_message.Message,), {
+  'DESCRIPTOR' : _ARGUMENTRANGE,
+  '__module__' : 'cirq.google.api.v2.device_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ArgumentRange)
-  ))
+  })
 _sym_db.RegisterMessage(ArgumentRange)
 
-TargetSet = _reflection.GeneratedProtocolMessageType('TargetSet', (_message.Message,), dict(
-  DESCRIPTOR = _TARGETSET,
-  __module__ = 'cirq.google.api.v2.device_pb2'
+TargetSet = _reflection.GeneratedProtocolMessageType('TargetSet', (_message.Message,), {
+  'DESCRIPTOR' : _TARGETSET,
+  '__module__' : 'cirq.google.api.v2.device_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.TargetSet)
-  ))
+  })
 _sym_db.RegisterMessage(TargetSet)
 
-Target = _reflection.GeneratedProtocolMessageType('Target', (_message.Message,), dict(
-  DESCRIPTOR = _TARGET,
-  __module__ = 'cirq.google.api.v2.device_pb2'
+Target = _reflection.GeneratedProtocolMessageType('Target', (_message.Message,), {
+  'DESCRIPTOR' : _TARGET,
+  '__module__' : 'cirq.google.api.v2.device_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Target)
-  ))
+  })
 _sym_db.RegisterMessage(Target)
 
 
diff --git a/cirq/google/api/v2/metrics_pb2.py b/cirq/google/api/v2/metrics_pb2.py
index 37d6e05c90f6..65936a5c1c0f 100644
--- a/cirq/google/api/v2/metrics_pb2.py
+++ b/cirq/google/api/v2/metrics_pb2.py
@@ -182,25 +182,25 @@
 DESCRIPTOR.message_types_by_name['Value'] = _VALUE
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-MetricsSnapshot = _reflection.GeneratedProtocolMessageType('MetricsSnapshot', (_message.Message,), dict(
-  DESCRIPTOR = _METRICSSNAPSHOT,
-  __module__ = 'cirq.google.api.v2.metrics_pb2'
+MetricsSnapshot = _reflection.GeneratedProtocolMessageType('MetricsSnapshot', (_message.Message,), {
+  'DESCRIPTOR' : _METRICSSNAPSHOT,
+  '__module__' : 'cirq.google.api.v2.metrics_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.MetricsSnapshot)
-  ))
+  })
 _sym_db.RegisterMessage(MetricsSnapshot)
 
-Metric = _reflection.GeneratedProtocolMessageType('Metric', (_message.Message,), dict(
-  DESCRIPTOR = _METRIC,
-  __module__ = 'cirq.google.api.v2.metrics_pb2'
+Metric = _reflection.GeneratedProtocolMessageType('Metric', (_message.Message,), {
+  'DESCRIPTOR' : _METRIC,
+  '__module__' : 'cirq.google.api.v2.metrics_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Metric)
-  ))
+  })
 _sym_db.RegisterMessage(Metric)
 
-Value = _reflection.GeneratedProtocolMessageType('Value', (_message.Message,), dict(
-  DESCRIPTOR = _VALUE,
-  __module__ = 'cirq.google.api.v2.metrics_pb2'
+Value = _reflection.GeneratedProtocolMessageType('Value', (_message.Message,), {
+  'DESCRIPTOR' : _VALUE,
+  '__module__' : 'cirq.google.api.v2.metrics_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Value)
-  ))
+  })
 _sym_db.RegisterMessage(Value)
 
 
diff --git a/cirq/google/api/v2/program_pb2.py b/cirq/google/api/v2/program_pb2.py
index c7784c3fac73..1cb4dbb0f459 100644
--- a/cirq/google/api/v2/program_pb2.py
+++ b/cirq/google/api/v2/program_pb2.py
@@ -638,103 +638,103 @@
 DESCRIPTOR.message_types_by_name['ArgFunction'] = _ARGFUNCTION
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-Program = _reflection.GeneratedProtocolMessageType('Program', (_message.Message,), dict(
-  DESCRIPTOR = _PROGRAM,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Program = _reflection.GeneratedProtocolMessageType('Program', (_message.Message,), {
+  'DESCRIPTOR' : _PROGRAM,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Program)
-  ))
+  })
 _sym_db.RegisterMessage(Program)
 
-Circuit = _reflection.GeneratedProtocolMessageType('Circuit', (_message.Message,), dict(
-  DESCRIPTOR = _CIRCUIT,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Circuit = _reflection.GeneratedProtocolMessageType('Circuit', (_message.Message,), {
+  'DESCRIPTOR' : _CIRCUIT,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Circuit)
-  ))
+  })
 _sym_db.RegisterMessage(Circuit)
 
-Moment = _reflection.GeneratedProtocolMessageType('Moment', (_message.Message,), dict(
-  DESCRIPTOR = _MOMENT,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Moment = _reflection.GeneratedProtocolMessageType('Moment', (_message.Message,), {
+  'DESCRIPTOR' : _MOMENT,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Moment)
-  ))
+  })
 _sym_db.RegisterMessage(Moment)
 
-Schedule = _reflection.GeneratedProtocolMessageType('Schedule', (_message.Message,), dict(
-  DESCRIPTOR = _SCHEDULE,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Schedule = _reflection.GeneratedProtocolMessageType('Schedule', (_message.Message,), {
+  'DESCRIPTOR' : _SCHEDULE,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Schedule)
-  ))
+  })
 _sym_db.RegisterMessage(Schedule)
 
-ScheduledOperation = _reflection.GeneratedProtocolMessageType('ScheduledOperation', (_message.Message,), dict(
-  DESCRIPTOR = _SCHEDULEDOPERATION,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+ScheduledOperation = _reflection.GeneratedProtocolMessageType('ScheduledOperation', (_message.Message,), {
+  'DESCRIPTOR' : _SCHEDULEDOPERATION,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ScheduledOperation)
-  ))
+  })
 _sym_db.RegisterMessage(ScheduledOperation)
 
-Language = _reflection.GeneratedProtocolMessageType('Language', (_message.Message,), dict(
-  DESCRIPTOR = _LANGUAGE,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Language = _reflection.GeneratedProtocolMessageType('Language', (_message.Message,), {
+  'DESCRIPTOR' : _LANGUAGE,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Language)
-  ))
+  })
 _sym_db.RegisterMessage(Language)
 
-Operation = _reflection.GeneratedProtocolMessageType('Operation', (_message.Message,), dict(
+Operation = _reflection.GeneratedProtocolMessageType('Operation', (_message.Message,), {
 
-  ArgsEntry = _reflection.GeneratedProtocolMessageType('ArgsEntry', (_message.Message,), dict(
-    DESCRIPTOR = _OPERATION_ARGSENTRY,
-    __module__ = 'cirq.google.api.v2.program_pb2'
+  'ArgsEntry' : _reflection.GeneratedProtocolMessageType('ArgsEntry', (_message.Message,), {
+    'DESCRIPTOR' : _OPERATION_ARGSENTRY,
+    '__module__' : 'cirq.google.api.v2.program_pb2'
     # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Operation.ArgsEntry)
-    ))
+    })
   ,
-  DESCRIPTOR = _OPERATION,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+  'DESCRIPTOR' : _OPERATION,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Operation)
-  ))
+  })
 _sym_db.RegisterMessage(Operation)
 _sym_db.RegisterMessage(Operation.ArgsEntry)
 
-Gate = _reflection.GeneratedProtocolMessageType('Gate', (_message.Message,), dict(
-  DESCRIPTOR = _GATE,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Gate = _reflection.GeneratedProtocolMessageType('Gate', (_message.Message,), {
+  'DESCRIPTOR' : _GATE,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Gate)
-  ))
+  })
 _sym_db.RegisterMessage(Gate)
 
-Qubit = _reflection.GeneratedProtocolMessageType('Qubit', (_message.Message,), dict(
-  DESCRIPTOR = _QUBIT,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Qubit = _reflection.GeneratedProtocolMessageType('Qubit', (_message.Message,), {
+  'DESCRIPTOR' : _QUBIT,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Qubit)
-  ))
+  })
 _sym_db.RegisterMessage(Qubit)
 
-Arg = _reflection.GeneratedProtocolMessageType('Arg', (_message.Message,), dict(
-  DESCRIPTOR = _ARG,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+Arg = _reflection.GeneratedProtocolMessageType('Arg', (_message.Message,), {
+  'DESCRIPTOR' : _ARG,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Arg)
-  ))
+  })
 _sym_db.RegisterMessage(Arg)
 
-ArgValue = _reflection.GeneratedProtocolMessageType('ArgValue', (_message.Message,), dict(
-  DESCRIPTOR = _ARGVALUE,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+ArgValue = _reflection.GeneratedProtocolMessageType('ArgValue', (_message.Message,), {
+  'DESCRIPTOR' : _ARGVALUE,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ArgValue)
-  ))
+  })
 _sym_db.RegisterMessage(ArgValue)
 
-RepeatedBoolean = _reflection.GeneratedProtocolMessageType('RepeatedBoolean', (_message.Message,), dict(
-  DESCRIPTOR = _REPEATEDBOOLEAN,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+RepeatedBoolean = _reflection.GeneratedProtocolMessageType('RepeatedBoolean', (_message.Message,), {
+  'DESCRIPTOR' : _REPEATEDBOOLEAN,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.RepeatedBoolean)
-  ))
+  })
 _sym_db.RegisterMessage(RepeatedBoolean)
 
-ArgFunction = _reflection.GeneratedProtocolMessageType('ArgFunction', (_message.Message,), dict(
-  DESCRIPTOR = _ARGFUNCTION,
-  __module__ = 'cirq.google.api.v2.program_pb2'
+ArgFunction = _reflection.GeneratedProtocolMessageType('ArgFunction', (_message.Message,), {
+  'DESCRIPTOR' : _ARGFUNCTION,
+  '__module__' : 'cirq.google.api.v2.program_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ArgFunction)
-  ))
+  })
 _sym_db.RegisterMessage(ArgFunction)
 
 
diff --git a/cirq/google/api/v2/result_pb2.py b/cirq/google/api/v2/result_pb2.py
index 7471dfc058d3..79f7e34d51ae 100644
--- a/cirq/google/api/v2/result_pb2.py
+++ b/cirq/google/api/v2/result_pb2.py
@@ -294,53 +294,53 @@
 DESCRIPTOR.message_types_by_name['ParameterDict'] = _PARAMETERDICT
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-Result = _reflection.GeneratedProtocolMessageType('Result', (_message.Message,), dict(
-  DESCRIPTOR = _RESULT,
-  __module__ = 'cirq.google.api.v2.result_pb2'
+Result = _reflection.GeneratedProtocolMessageType('Result', (_message.Message,), {
+  'DESCRIPTOR' : _RESULT,
+  '__module__' : 'cirq.google.api.v2.result_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Result)
-  ))
+  })
 _sym_db.RegisterMessage(Result)
 
-SweepResult = _reflection.GeneratedProtocolMessageType('SweepResult', (_message.Message,), dict(
-  DESCRIPTOR = _SWEEPRESULT,
-  __module__ = 'cirq.google.api.v2.result_pb2'
+SweepResult = _reflection.GeneratedProtocolMessageType('SweepResult', (_message.Message,), {
+  'DESCRIPTOR' : _SWEEPRESULT,
+  '__module__' : 'cirq.google.api.v2.result_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.SweepResult)
-  ))
+  })
 _sym_db.RegisterMessage(SweepResult)
 
-ParameterizedResult = _reflection.GeneratedProtocolMessageType('ParameterizedResult', (_message.Message,), dict(
-  DESCRIPTOR = _PARAMETERIZEDRESULT,
-  __module__ = 'cirq.google.api.v2.result_pb2'
+ParameterizedResult = _reflection.GeneratedProtocolMessageType('ParameterizedResult', (_message.Message,), {
+  'DESCRIPTOR' : _PARAMETERIZEDRESULT,
+  '__module__' : 'cirq.google.api.v2.result_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ParameterizedResult)
-  ))
+  })
 _sym_db.RegisterMessage(ParameterizedResult)
 
-MeasurementResult = _reflection.GeneratedProtocolMessageType('MeasurementResult', (_message.Message,), dict(
-  DESCRIPTOR = _MEASUREMENTRESULT,
-  __module__ = 'cirq.google.api.v2.result_pb2'
+MeasurementResult = _reflection.GeneratedProtocolMessageType('MeasurementResult', (_message.Message,), {
+  'DESCRIPTOR' : _MEASUREMENTRESULT,
+  '__module__' : 'cirq.google.api.v2.result_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.MeasurementResult)
-  ))
+  })
 _sym_db.RegisterMessage(MeasurementResult)
 
-QubitMeasurementResult = _reflection.GeneratedProtocolMessageType('QubitMeasurementResult', (_message.Message,), dict(
-  DESCRIPTOR = _QUBITMEASUREMENTRESULT,
-  __module__ = 'cirq.google.api.v2.result_pb2'
+QubitMeasurementResult = _reflection.GeneratedProtocolMessageType('QubitMeasurementResult', (_message.Message,), {
+  'DESCRIPTOR' : _QUBITMEASUREMENTRESULT,
+  '__module__' : 'cirq.google.api.v2.result_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.QubitMeasurementResult)
-  ))
+  })
 _sym_db.RegisterMessage(QubitMeasurementResult)
 
-ParameterDict = _reflection.GeneratedProtocolMessageType('ParameterDict', (_message.Message,), dict(
+ParameterDict = _reflection.GeneratedProtocolMessageType('ParameterDict', (_message.Message,), {
 
-  AssignmentsEntry = _reflection.GeneratedProtocolMessageType('AssignmentsEntry', (_message.Message,), dict(
-    DESCRIPTOR = _PARAMETERDICT_ASSIGNMENTSENTRY,
-    __module__ = 'cirq.google.api.v2.result_pb2'
+  'AssignmentsEntry' : _reflection.GeneratedProtocolMessageType('AssignmentsEntry', (_message.Message,), {
+    'DESCRIPTOR' : _PARAMETERDICT_ASSIGNMENTSENTRY,
+    '__module__' : 'cirq.google.api.v2.result_pb2'
     # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ParameterDict.AssignmentsEntry)
-    ))
+    })
   ,
-  DESCRIPTOR = _PARAMETERDICT,
-  __module__ = 'cirq.google.api.v2.result_pb2'
+  'DESCRIPTOR' : _PARAMETERDICT,
+  '__module__' : 'cirq.google.api.v2.result_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ParameterDict)
-  ))
+  })
 _sym_db.RegisterMessage(ParameterDict)
 _sym_db.RegisterMessage(ParameterDict.AssignmentsEntry)
 
diff --git a/cirq/google/api/v2/run_context_pb2.py b/cirq/google/api/v2/run_context_pb2.py
index e017add9d68a..dfb8dd7096c7 100644
--- a/cirq/google/api/v2/run_context_pb2.py
+++ b/cirq/google/api/v2/run_context_pb2.py
@@ -354,53 +354,53 @@
 DESCRIPTOR.message_types_by_name['Linspace'] = _LINSPACE
 _sym_db.RegisterFileDescriptor(DESCRIPTOR)
 
-RunContext = _reflection.GeneratedProtocolMessageType('RunContext', (_message.Message,), dict(
-  DESCRIPTOR = _RUNCONTEXT,
-  __module__ = 'cirq.google.api.v2.run_context_pb2'
+RunContext = _reflection.GeneratedProtocolMessageType('RunContext', (_message.Message,), {
+  'DESCRIPTOR' : _RUNCONTEXT,
+  '__module__' : 'cirq.google.api.v2.run_context_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.RunContext)
-  ))
+  })
 _sym_db.RegisterMessage(RunContext)
 
-ParameterSweep = _reflection.GeneratedProtocolMessageType('ParameterSweep', (_message.Message,), dict(
-  DESCRIPTOR = _PARAMETERSWEEP,
-  __module__ = 'cirq.google.api.v2.run_context_pb2'
+ParameterSweep = _reflection.GeneratedProtocolMessageType('ParameterSweep', (_message.Message,), {
+  'DESCRIPTOR' : _PARAMETERSWEEP,
+  '__module__' : 'cirq.google.api.v2.run_context_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.ParameterSweep)
-  ))
+  })
 _sym_db.RegisterMessage(ParameterSweep)
 
-Sweep = _reflection.GeneratedProtocolMessageType('Sweep', (_message.Message,), dict(
-  DESCRIPTOR = _SWEEP,
-  __module__ = 'cirq.google.api.v2.run_context_pb2'
+Sweep = _reflection.GeneratedProtocolMessageType('Sweep', (_message.Message,), {
+  'DESCRIPTOR' : _SWEEP,
+  '__module__' : 'cirq.google.api.v2.run_context_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Sweep)
-  ))
+  })
 _sym_db.RegisterMessage(Sweep)
 
-SweepFunction = _reflection.GeneratedProtocolMessageType('SweepFunction', (_message.Message,), dict(
-  DESCRIPTOR = _SWEEPFUNCTION,
-  __module__ = 'cirq.google.api.v2.run_context_pb2'
+SweepFunction = _reflection.GeneratedProtocolMessageType('SweepFunction', (_message.Message,), {
+  'DESCRIPTOR' : _SWEEPFUNCTION,
+  '__module__' : 'cirq.google.api.v2.run_context_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.SweepFunction)
-  ))
+  })
 _sym_db.RegisterMessage(SweepFunction)
 
-SingleSweep = _reflection.GeneratedProtocolMessageType('SingleSweep', (_message.Message,), dict(
-  DESCRIPTOR = _SINGLESWEEP,
-  __module__ = 'cirq.google.api.v2.run_context_pb2'
+SingleSweep = _reflection.GeneratedProtocolMessageType('SingleSweep', (_message.Message,), {
+  'DESCRIPTOR' : _SINGLESWEEP,
+  '__module__' : 'cirq.google.api.v2.run_context_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.SingleSweep)
-  ))
+  })
 _sym_db.RegisterMessage(SingleSweep)
 
-Points = _reflection.GeneratedProtocolMessageType('Points', (_message.Message,), dict(
-  DESCRIPTOR = _POINTS,
-  __module__ = 'cirq.google.api.v2.run_context_pb2'
+Points = _reflection.GeneratedProtocolMessageType('Points', (_message.Message,), {
+  'DESCRIPTOR' : _POINTS,
+  '__module__' : 'cirq.google.api.v2.run_context_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Points)
-  ))
+  })
 _sym_db.RegisterMessage(Points)
 
-Linspace = _reflection.GeneratedProtocolMessageType('Linspace', (_message.Message,), dict(
-  DESCRIPTOR = _LINSPACE,
-  __module__ = 'cirq.google.api.v2.run_context_pb2'
+Linspace = _reflection.GeneratedProtocolMessageType('Linspace', (_message.Message,), {
+  'DESCRIPTOR' : _LINSPACE,
+  '__module__' : 'cirq.google.api.v2.run_context_pb2'
   # @@protoc_insertion_point(class_scope:cirq.google.api.v2.Linspace)
-  ))
+  })
 _sym_db.RegisterMessage(Linspace)
 
 
diff --git a/cirq/google/engine/engine_job.py b/cirq/google/engine/engine_job.py
index 78a006d7366d..a3cad072867a 100644
--- a/cirq/google/engine/engine_job.py
+++ b/cirq/google/engine/engine_job.py
@@ -213,8 +213,8 @@ def _deserialize_run_context(run_context: quantum.types.any_pb2.Any
             raise ValueError('deserializing a v1 RunContext is not supported')
         if (run_context_type == 'cirq.google.api.v2.RunContext' or
                 run_context_type == 'cirq.api.google.v2.RunContext'):
-            v2_run_context = v2.run_context_pb2.RunContext()
-            v2_run_context.ParseFromString(run_context.value)
+            v2_run_context = v2.run_context_pb2.RunContext.FromString(
+                run_context.value)
             return v2_run_context.parameter_sweeps[0].repetitions, [
                 v2.sweep_from_proto(s.sweep)
                 for s in v2_run_context.parameter_sweeps
@@ -242,8 +242,7 @@ def get_calibration(self) -> Optional[calibration.Calibration]:
         ids = self.context.client._ids_from_calibration_name(
             status.calibration_name)
         response = self.context.client.get_calibration(*ids)
-        metrics = v2.metrics_pb2.MetricsSnapshot()
-        metrics.ParseFromString(response.data.value)
+        metrics = v2.metrics_pb2.MetricsSnapshot.FromString(response.data.value)
         return calibration.Calibration(metrics)
 
     def cancel(self) -> None:
@@ -279,13 +278,12 @@ def results(self) -> List[study.TrialResult]:
             result_type = result.type_url[len(engine_base.TYPE_PREFIX):]
             if (result_type == 'cirq.google.api.v1.Result' or
                     result_type == 'cirq.api.google.v1.Result'):
-                v1_parsed_result = v1.program_pb2.Result()
-                v1_parsed_result.ParseFromString(result.value)
+                v1_parsed_result = v1.program_pb2.Result.FromString(
+                    result.value)
                 self._results = self._get_job_results_v1(v1_parsed_result)
             elif (result_type == 'cirq.google.api.v2.Result' or
                   result_type == 'cirq.api.google.v2.Result'):
-                v2_parsed_result = v2.result_pb2.Result()
-                v2_parsed_result.ParseFromString(result.value)
+                v2_parsed_result = v2.result_pb2.Result.FromString(result.value)
                 self._results = self._get_job_results_v2(v2_parsed_result)
             else:
                 raise ValueError(
diff --git a/cirq/google/engine/engine_processor.py b/cirq/google/engine/engine_processor.py
index d405443066fb..b49ca6da8b07 100644
--- a/cirq/google/engine/engine_processor.py
+++ b/cirq/google/engine/engine_processor.py
@@ -104,10 +104,8 @@ def get_device_specification(
             Device specification proto if present.
         """
         if self._inner_processor().HasField('device_spec'):
-            device_spec = v2.device_pb2.DeviceSpecification()
-            device_spec.ParseFromString(
+            return v2.device_pb2.DeviceSpecification.FromString(
                 self._inner_processor().device_spec.value)
-            return device_spec
         else:
             return None
 
@@ -129,8 +127,8 @@ def get_device(
     @staticmethod
     def _to_calibration(calibration_any: qtypes.any_pb2.Any
                        ) -> calibration.Calibration:
-        metrics = v2.metrics_pb2.MetricsSnapshot()
-        metrics.ParseFromString(calibration_any.value)
+        metrics = v2.metrics_pb2.MetricsSnapshot.FromString(
+            calibration_any.value)
         return calibration.Calibration(metrics)
 
     def list_calibrations(self,
diff --git a/cirq/google/engine/engine_program.py b/cirq/google/engine/engine_program.py
index b14635660194..bf90e18130e4 100644
--- a/cirq/google/engine/engine_program.py
+++ b/cirq/google/engine/engine_program.py
@@ -283,8 +283,7 @@ def _deserialize_program(code: qtypes.any_pb2.Any) -> 'Circuit':
             raise ValueError('deserializing a v1 Program is not supported')
         if (code_type == 'cirq.google.api.v2.Program' or
                 code_type == 'cirq.api.google.v2.Program'):
-            program = v2.program_pb2.Program()
-            program.ParseFromString(code.value)
+            program = v2.program_pb2.Program.FromString(code.value)
             gate_set_map = {
                 g.gate_set_name: g for g in gate_sets.GOOGLE_GATESETS
             }
diff --git a/cirq/ion/ion_gates.py b/cirq/ion/ion_gates.py
index 82593e464681..d91f694a61b4 100644
--- a/cirq/ion/ion_gates.py
+++ b/cirq/ion/ion_gates.py
@@ -14,12 +14,17 @@
 
 """Operations native to iontrap systems."""
 
+from typing import Union, TYPE_CHECKING
 import numpy as np
 
-from cirq import ops
+from cirq import ops, value
+from cirq import protocols
 
+if TYPE_CHECKING:
+    import cirq
 
-def ms(rads: float) -> ops.XXPowGate:
+
+class MSGate(ops.XXPowGate):
     """The Mølmer–Sørensen gate, a native two-qubit operation in ion traps.
 
     A rotation around the XX axis in the two-qubit bloch sphere.
@@ -30,11 +35,42 @@ def ms(rads: float) -> ops.XXPowGate:
                        [ 0        cos(t)  -isin(t)  0      ]
                        [ 0       -isin(t)  cos(t)   0      ]
                        [-isin(t)  0        0        cos(t) ]
+    """
+
+    def __init__(
+            self,
+            *,  # Forces keyword args.
+            rads: float):
+        ops.XXPowGate.__init__(self,
+                               exponent=rads * 2 / np.pi,
+                               global_shift=-0.5)
+
+    def _with_exponent(self: 'MSGate', exponent: value.TParamVal) -> 'MSGate':
+        return type(self)(rads=exponent * np.pi / 2)
+
+    def _circuit_diagram_info_(self, args: 'cirq.CircuitDiagramInfoArgs'
+                              ) -> Union[str, 'protocols.CircuitDiagramInfo']:
+        angle_str = self._format_exponent_as_angle(args, order=4)
+        symbol = f'MS({angle_str})'
+        return protocols.CircuitDiagramInfo(wire_symbols=(symbol, symbol))
 
+    def __str__(self) -> str:
+        if self._exponent == 1:
+            return 'MS(π/2)'
+        return f'MS({self._exponent!r}π/2)'
+
+    def __repr__(self) -> str:
+        if self._exponent == 1:
+            return 'cirq.ms(np.pi/2)'
+        return f'cirq.ms({self._exponent!r}*np.pi/2)'
+
+
+def ms(rads: float) -> MSGate:
+    """
     Args:
         rads: The rotation angle in radians.
 
     Returns:
         Mølmer–Sørensen gate rotating by the desired amount.
     """
-    return ops.XXPowGate(exponent=rads * 2 / np.pi, global_shift=-0.5)
+    return MSGate(rads=rads)
diff --git a/cirq/ion/ion_gates_test.py b/cirq/ion/ion_gates_test.py
index 52ddcb10084e..979f330a6264 100644
--- a/cirq/ion/ion_gates_test.py
+++ b/cirq/ion/ion_gates_test.py
@@ -20,12 +20,17 @@
 def test_ms_arguments():
     eq_tester = cirq.testing.EqualsTester()
     eq_tester.add_equality_group(cirq.ms(np.pi / 2),
-                                 cirq.XXPowGate(global_shift=-0.5))
+                                 cirq.ion.ion_gates.MSGate(rads=np.pi / 2))
+    eq_tester.add_equality_group(cirq.XXPowGate(global_shift=-0.5))
 
 
 def test_ms_str():
-    assert str(cirq.ms(np.pi / 2)) == 'MS(π/2)'
+    ms = cirq.ms(np.pi / 2)
+    assert str(ms) == 'MS(π/2)'
     assert str(cirq.ms(np.pi)) == 'MS(2.0π/2)'
+    assert str(ms**0.5) == 'MS(0.5π/2)'
+    assert str(ms**2) == 'MS(2.0π/2)'
+    assert str(ms**-1) == 'MS(-1.0π/2)'
 
 
 def test_ms_matrix():
@@ -47,6 +52,9 @@ def test_ms_repr():
     assert repr(cirq.ms(np.pi / 2)) == 'cirq.ms(np.pi/2)'
     assert repr(cirq.ms(np.pi / 4)) == 'cirq.ms(0.5*np.pi/2)'
     cirq.testing.assert_equivalent_repr(cirq.ms(np.pi / 4))
+    ms = cirq.ms(np.pi / 2)
+    assert (repr(ms**2) == 'cirq.ms(2.0*np.pi/2)')
+    assert (repr(ms**-0.5) == 'cirq.ms(-0.5*np.pi/2)')
 
 
 def test_ms_diagrams():
diff --git a/cirq/ops/parity_gates.py b/cirq/ops/parity_gates.py
index 8b022d5510b3..13b698b0b584 100644
--- a/cirq/ops/parity_gates.py
+++ b/cirq/ops/parity_gates.py
@@ -39,7 +39,7 @@ class XXPowGate(eigen_gate.EigenGate,
               [0 1 0 0]
               [1 0 0 0]
 
-    See also: `cirq.MS` (the Mølmer–Sørensen gate), which is implemented via
+    See also: `cirq.MSGate` (the Mølmer–Sørensen gate), which is implemented via
         this class.
     """
 
@@ -86,13 +86,6 @@ def _decompose_into_clifford_with_qubits_(self, qubits):
 
     def _circuit_diagram_info_(self, args: 'cirq.CircuitDiagramInfoArgs'
                               ) -> Union[str, 'protocols.CircuitDiagramInfo']:
-        if self._global_shift == -0.5:
-            # Mølmer–Sørensen gate.
-            angle_str = self._format_exponent_as_angle(args, order=4)
-            symbol = f'MS({angle_str})'
-            return protocols.CircuitDiagramInfo(
-                                wire_symbols=(symbol, symbol))
-
         return protocols.CircuitDiagramInfo(
             wire_symbols=('XX', 'XX'),
             exponent=self._diagram_exponent(args))
@@ -105,19 +98,11 @@ def _quil_(self, qubits: Tuple['cirq.Qid', ...],
                                 qubits[0], self._exponent, qubits[1])
 
     def __str__(self) -> str:
-        if self._global_shift == -0.5:
-            if self._exponent == 1:
-                return 'MS(π/2)'
-            return f'MS({self._exponent!r}π/2)'
         if self.exponent == 1:
             return 'XX'
         return f'XX**{self._exponent!r}'
 
     def __repr__(self) -> str:
-        if self._global_shift == -0.5 and not protocols.is_parameterized(self):
-            if self._exponent == 1:
-                return 'cirq.ms(np.pi/2)'
-            return f'cirq.ms({self._exponent!r}*np.pi/2)'
         if self._global_shift == 0:
             if self._exponent == 1:
                 return 'cirq.XX'
diff --git a/cirq/ops/parity_gates_test.py b/cirq/ops/parity_gates_test.py
index 16b9277814a3..74fa36baff05 100644
--- a/cirq/ops/parity_gates_test.py
+++ b/cirq/ops/parity_gates_test.py
@@ -63,23 +63,10 @@ def test_xx_str():
     assert str(cirq.XX**0.5) == 'XX**0.5'
     assert str(cirq.XXPowGate(global_shift=0.1)) == 'XX'
 
-    ms = cirq.XXPowGate(global_shift=-0.5)
-    assert str(ms) == 'MS(π/2)'
-    assert str(ms**0.5) == 'MS(0.5π/2)'
-    assert str(ms**2) == 'MS(2.0π/2)'
-    assert str(ms**-1) == 'MS(-1.0π/2)'
-
-
 def test_xx_repr():
     assert repr(cirq.XXPowGate()) == 'cirq.XX'
     assert repr(cirq.XXPowGate(exponent=0.5)) == '(cirq.XX**0.5)'
 
-    ms = cirq.XXPowGate(global_shift=-0.5)
-    assert (repr(ms) == 'cirq.ms(np.pi/2)')
-    assert (repr(ms**2) == 'cirq.ms(2.0*np.pi/2)')
-    assert (repr(ms**-0.5) == 'cirq.ms(-0.5*np.pi/2)')
-
-
 def test_xx_matrix():
     np.testing.assert_allclose(cirq.unitary(cirq.XX),
                                np.array([[0, 0, 0, 1],
@@ -109,13 +96,12 @@ def test_xx_diagrams():
         cirq.XX(a, b),
         cirq.XX(a, b)**3,
         cirq.XX(a, b)**0.5,
-        cirq.XXPowGate(global_shift=-0.5).on(a, b),
     )
     cirq.testing.assert_has_diagram(
         circuit, """
-a: ───XX───XX───XX───────MS(0.5π)───
-      │    │    │        │
-b: ───XX───XX───XX^0.5───MS(0.5π)───
+a: ───XX───XX───XX───────
+      │    │    │
+b: ───XX───XX───XX^0.5───
 """)
 
 
diff --git a/docs/api.rst b/docs/api.rst
index 8bcc6874d88a..afb9eee8f746 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -239,6 +239,7 @@ results.
     cirq.sample_sweep
     cirq.to_resolvers
     cirq.to_sweep
+    cirq.to_sweeps
     cirq.validate_mixture
     cirq.validate_probability
     cirq.xeb_fidelity
@@ -349,6 +350,7 @@ the magic methods that can be implemented.
     cirq.resolve_parameters
     cirq.to_json
     cirq.trace_distance_bound
+    cirq.trace_distance_from_angle_list
     cirq.unitary
     cirq.ApplyChannelArgs
     cirq.ApplyMixtureArgs
@@ -621,6 +623,7 @@ Algebra and Representation
     cirq.chosen_angle_to_canonical_half_turns
     cirq.chosen_angle_to_half_turns
     cirq.commutes
+    cirq.deconstruct_single_qubit_matrix_into_angles
     cirq.definitely_commutes
     cirq.diagonalize_real_symmetric_and_sorted_diagonal_matrices
     cirq.diagonalize_real_symmetric_matrix
@@ -644,6 +647,7 @@ Algebra and Representation
     cirq.kron_with_controls
     cirq.map_eigenvalues
     cirq.match_global_phase
+    cirq.matrix_commutes
     cirq.matrix_from_basis_coefficients
     cirq.partial_trace
     cirq.partial_trace_of_state_vector_as_mixture
@@ -675,6 +679,7 @@ Quantum Information Science
     cirq.one_hot
     cirq.to_valid_density_matrix
     cirq.to_valid_state_vector
+    cirq.validate_indices
     cirq.validate_normalized_state_vector
     cirq.validate_qid_shape
     cirq.von_neumann_entropy