Stop using native.http_archive and native.http_file

Change-Id: I69552fa4a119873081738b180eb5eebc4c840064

gerrit_polymer.bzl

@@ -1,7 +1,7 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive", "http_file")
 
 def gerrit_polymer():
-    native.http_archive(
+    http_archive(
         name = "io_bazel_rules_closure",
         sha256 = "d797d2410358bc8a4ceb1d26319b899acf4201f39cf2a99eb4b57212c01d76c7",
         strip_prefix = "rules_closure-a34455e0c76769df13d25b67851252559fe7f83d",
@@ -11,7 +11,7 @@ def gerrit_polymer():
     # File is specific to Polymer and copied from the Closure Github -- should be
     # synced any time there are major changes to Polymer.
     # https://github.com/google/closure-compiler/blob/master/contrib/externs/polymer-1.0.js
-    native.http_file(
+    http_file(
         name = "polymer_closure",
         sha256 = "5a589bdba674e1fec7188e9251c8624ebf2d4d969beb6635f9148f420d1e08b1",
         urls = ["https://raw.githubusercontent.com/google/closure-compiler/775609aad61e14aef289ebec4bfc09ad88877f9e/contrib/externs/polymer-1.0.js"],