diff --git a/pkg/dart2js_info/bin/src/runtime_coverage_analysis.dart b/pkg/dart2js_info/bin/src/runtime_coverage_analysis.dart
index 9d4bcbed360b..eea5e1d1f757 100644
--- a/pkg/dart2js_info/bin/src/runtime_coverage_analysis.dart
+++ b/pkg/dart2js_info/bin/src/runtime_coverage_analysis.dart
@@ -35,6 +35,7 @@ import 'package:collection/collection.dart';
 import 'package:dart2js_info/info.dart';
 import 'package:dart2js_info/src/io.dart';
 import 'package:dart2js_info/src/util.dart';
+import 'package:dart2js_info/src/runtime_coverage_utils.dart';
 
 import 'usage_exception.dart';
 
@@ -274,12 +275,9 @@ Future<void> _reportWithClassFilter(
   // The value associated with each coverage item isn't used for now.
   Set<String> coverage = coverageRaw.keys.toSet();
 
-  final classFilterData = <String, RuntimeClassInfo>{};
-  for (final runtimeClassInfo in File(filterFile)
-      .readAsLinesSync()
-      .map((l) => RuntimeClassInfo.fromAngularInfo(l))) {
-    classFilterData[runtimeClassInfo.key] = runtimeClassInfo;
-  }
+  final classFilterData = {
+    for (final info in runtimeInfoFromAngularInfo(filterFile)) info.key: info
+  };
 
   // Ensure that a used class's super, mixed in, and implemented classes are
   // correctly marked as used.
@@ -445,88 +443,3 @@ void _show(String msg, int size, int total) {
 void _leftPadded(String msg1, String msg2) {
   print(' ${pad(msg1, 50, right: true)} $msg2');
 }
-
-class RuntimePackageInfo {
-  final elements = PriorityQueue<BasicInfo>((a, b) => b.size.compareTo(a.size));
-
-  num mainUnitSize = 0;
-  num totalSize = 0;
-  num unusedMainUnitSize = 0;
-  num unusedSize = 0;
-  num usedRatio = 0;
-  num usedSize = 0;
-
-  RuntimePackageInfo();
-
-  void add(BasicInfo i, {bool used = true}) {
-    totalSize += i.size;
-    if (used) {
-      usedSize += i.size;
-    } else {
-      unusedSize += i.size;
-    }
-    if (i.outputUnit!.name == 'main') {
-      mainUnitSize += i.size;
-      if (!used) {
-        unusedMainUnitSize += i.size;
-      }
-    }
-    elements.add(i);
-    usedRatio = usedSize / totalSize;
-  }
-}
-
-class RuntimeClassInfo {
-  late String scheme;
-  late String package;
-  late String? path;
-  late String name;
-
-  late num size;
-  late bool used;
-  late bool inMainUnit;
-  late ClassInfo info;
-
-  bool annotated = false;
-
-  RuntimeClassInfo();
-
-  /// Ingests the output from Angular's info generator.
-  ///
-  /// Example: 'fully:qualified/path/to/file.dart - ClassName'
-  RuntimeClassInfo.fromAngularInfo(String input) {
-    final colonIndex = input.indexOf(':');
-    if (colonIndex < 0) {
-      throw ArgumentError('AngularInfo format cannot accept undefined schemes.'
-          ' No scheme found for: $input');
-    }
-    final slashIndex = input.indexOf('/');
-    final spaceIndex = input.indexOf(' ');
-    final separatorSize = ' - '.length;
-    scheme = input.substring(0, colonIndex);
-    if (slashIndex < 0) {
-      path = null;
-      package = input.substring(colonIndex + 1, spaceIndex);
-    } else {
-      package = input.substring(colonIndex + 1, slashIndex);
-      path = input.substring(slashIndex + 1, spaceIndex);
-    }
-    name = input.substring(spaceIndex + separatorSize, input.length);
-  }
-
-  String get key =>
-      '$package${path == null ? '' : '/$path'}:$name'.replaceAll('/lib/', '/');
-
-  void annotateWithClassInfo(ClassInfo i, {bool used = true}) {
-    size = i.size;
-    this.used = used;
-    inMainUnit = i.outputUnit!.name == 'main';
-    info = i;
-    annotated = true;
-  }
-
-  @override
-  String toString() {
-    return '$package/$path - $name';
-  }
-}
diff --git a/pkg/dart2js_info/lib/src/runtime_coverage_utils.dart b/pkg/dart2js_info/lib/src/runtime_coverage_utils.dart
new file mode 100644
index 000000000000..04a13562312d
--- /dev/null
+++ b/pkg/dart2js_info/lib/src/runtime_coverage_utils.dart
@@ -0,0 +1,117 @@
+import 'dart:io';
+
+import 'package:collection/collection.dart';
+import 'package:dart2js_info/info.dart';
+
+List<RuntimeClassInfo> runtimeInfoFromAngularInfo(String angularInfoFilePath) {
+  final angularInfoFile = File(angularInfoFilePath);
+  final runtimeInfo = <RuntimeClassInfo>[];
+  final separator = ' - ';
+  for (final line in angularInfoFile.readAsLinesSync()) {
+    // Ignore lines without two ' - ' separators.
+    if (separator.allMatches(line).length != 2) continue;
+    runtimeInfo.add(RuntimeClassInfo.fromAngularInfo(line));
+  }
+  return runtimeInfo;
+}
+
+class RuntimePackageInfo {
+  final elements = PriorityQueue<BasicInfo>((a, b) => b.size.compareTo(a.size));
+
+  num mainUnitSize = 0;
+  num totalSize = 0;
+  num unusedMainUnitSize = 0;
+  num unusedSize = 0;
+  num usedRatio = 0;
+  num usedSize = 0;
+
+  RuntimePackageInfo();
+
+  void add(BasicInfo i, {bool used = true}) {
+    totalSize += i.size;
+    if (used) {
+      usedSize += i.size;
+    } else {
+      unusedSize += i.size;
+    }
+    if (i.outputUnit!.name == 'main') {
+      mainUnitSize += i.size;
+      if (!used) {
+        unusedMainUnitSize += i.size;
+      }
+    }
+    elements.add(i);
+    usedRatio = usedSize / totalSize;
+  }
+}
+
+class RuntimeClassInfo {
+  late String scheme;
+  late String package;
+  late String? path;
+  late String name;
+
+  late num size;
+  late bool used;
+  late bool inMainUnit;
+  late ClassInfo info;
+
+  bool annotated = false;
+
+  RuntimeClassInfo();
+
+  RuntimeClassInfo.fromQualifiedName(String qualifiedName) {
+    final colonIndex = qualifiedName.indexOf(':');
+    final slashIndex = qualifiedName.indexOf('/');
+    final colonIndex2 = qualifiedName.lastIndexOf(':');
+    scheme = qualifiedName.substring(0, colonIndex);
+    package = qualifiedName.substring(colonIndex + 1, slashIndex);
+    path = qualifiedName.substring(slashIndex + 1, colonIndex2);
+    name = qualifiedName.substring(colonIndex2 + 1, qualifiedName.length);
+  }
+
+  /// Ingests the output from Angular's info generator.
+  ///
+  /// Example: 'fully:qualified/path/to/file.dart - ClassName - 123 (bytes)'
+  RuntimeClassInfo.fromAngularInfo(String rawInput) {
+    final separator = ' - ';
+    final separatorSize = separator.length;
+    // Remove the size specification.
+    var input = rawInput;
+    if (separator.allMatches(rawInput).length > 1) {
+      input = rawInput.substring(0, rawInput.lastIndexOf(separator));
+    }
+    final colonIndex = input.indexOf(':');
+    if (colonIndex < 0) {
+      throw ArgumentError('AngularInfo format cannot accept undefined schemes.'
+          ' No scheme found for: $input');
+    }
+    final slashIndex = input.indexOf('/');
+    final spaceIndex = input.indexOf(' ');
+    scheme = input.substring(0, colonIndex);
+    if (slashIndex < 0) {
+      path = null;
+      package = input.substring(colonIndex + 1, spaceIndex);
+    } else {
+      package = input.substring(colonIndex + 1, slashIndex);
+      path = input.substring(slashIndex + 1, spaceIndex);
+    }
+    name = input.substring(spaceIndex + separatorSize, input.length);
+  }
+
+  String get key =>
+      '$package${path == null ? '' : '/$path'}:$name'.replaceAll('/lib/', '/');
+
+  void annotateWithClassInfo(ClassInfo i, {bool used = true}) {
+    size = i.size;
+    this.used = used;
+    inMainUnit = i.outputUnit!.name == 'main';
+    info = i;
+    annotated = true;
+  }
+
+  @override
+  String toString() {
+    return '$package/$path - $name';
+  }
+}
diff --git a/pkg/dart2js_info/test/classes/class_filter.txt b/pkg/dart2js_info/test/classes/class_filter.txt
index aa011aa3d607..e1aec5bad8c8 100644
--- a/pkg/dart2js_info/test/classes/class_filter.txt
+++ b/pkg/dart2js_info/test/classes/class_filter.txt
@@ -1,5 +1,5 @@
-dart:_rti - _Universe
-dart:core - Error
-testroot:classes.dart - Subsub1
-testroot:classes.dart - Super
-package:expect/expect.dart - Expect
+dart:_rti - _Universe - 300 (bytes)
+dart:core - Error - 300 (bytes)
+testroot:classes.dart - Subsub1 - 300 (bytes)
+testroot:classes.dart - Super - 300 (bytes)
+package:expect/expect.dart - Expect - 300 (bytes)
diff --git a/pkg/dart2js_info/test/runtime_coverage_test.dart b/pkg/dart2js_info/test/runtime_coverage_test.dart
index 9d5d0484bce4..d73b8366437c 100644
--- a/pkg/dart2js_info/test/runtime_coverage_test.dart
+++ b/pkg/dart2js_info/test/runtime_coverage_test.dart
@@ -14,10 +14,10 @@
 import 'dart:io';
 
 import 'package:dart2js_info/binary_serialization.dart';
+import 'package:dart2js_info/src/runtime_coverage_utils.dart';
 import 'package:dart2js_info/src/util.dart';
-import 'package:test/test.dart';
 
-import '../bin/src/runtime_coverage_analysis.dart';
+import 'package:test/test.dart';
 
 void main() {
   group('runtime coverage', () {