Revert of Move gn _run target generation into test().

cc/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//testing/test.gni")
 
 component("cc") {
   sources = [
     "animation/animation.cc",
     "animation/animation.h",
@@ skipping 738 matching lines @@
     "//ui/gfx/geometry",
     "//ui/gl",
     "//ui/gl:test_support",
   ]
 
   if (!is_android) {  # TODO(GYP) Enable on Android when osmesa links.
     deps += [ "//third_party/mesa:osmesa" ]
   }
 }
 
+# TODO(GYP): Delete this after we've converted everything to GN.
+# The _run targets exist only for compatibility w/ GYP.
+group("cc_unittests_run") {
+  testonly = true
+  deps = [
+    ":cc_unittests",
+  ]
+}
+
 test("cc_unittests") {
   sources = [
     "animation/animation_host_unittest.cc",
     "animation/animation_player_unittest.cc",
     "animation/animation_timeline_unittest.cc",
     "animation/animation_unittest.cc",
     "animation/element_animations_unittest.cc",
     "animation/keyframed_animation_curve_unittest.cc",
     "animation/layer_animation_controller_unittest.cc",
     "animation/scroll_offset_animation_curve_unittest.cc",
@@ skipping 229 matching lines @@
     "//ui/gl",
     "//ui/gl:test_support",
   ]
 
   if (is_android) {
     isolate_file = "cc_perftests.isolate"
   }
 }
 # When adding support for isolates, please have a look at run-time dependencies
 # in the cc_unittests_run target in cc_tests.gyp.