Remove GYP annotations from third_party GN files.

third_party/WebKit/Source/modules/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("//build/split_static_library.gni")
 import("//build/config/chromecast_build.gni")
 import("//third_party/WebKit/Source/bindings/bindings.gni")
 import("//third_party/WebKit/Source/bindings/modules/v8/generated.gni")
 import("//third_party/WebKit/Source/bindings/modules/v8/v8.gni")
 import("//third_party/WebKit/Source/build/scripts/scripts.gni")
@@ skipping 151 matching lines @@
   if (is_win) {
     cflags = [ "/wd4334" ]  # Result of 32-bit shift implicitly converted to 64 bits.
   }
 
   if (remove_webcore_debug_symbols) {
     configs -= [ "//build/config/compiler:default_symbols" ]
     configs += [ "//build/config/compiler:no_symbols" ]
   }
 }
 
-# GYP version: WebKit/Source/modules/modules.gyp:modules_testing
 source_set("modules_testing") {
   sources = [
     "$bindings_modules_v8_output_dir/V8InternalsPartial.cpp",
     "$bindings_modules_v8_output_dir/V8InternalsPartial.h",
     "accessibility/testing/InternalsAccessibility.cpp",
     "accessibility/testing/InternalsAccessibility.h",
     "navigatorcontentutils/testing/InternalsNavigatorContentUtils.cpp",
     "navigatorcontentutils/testing/InternalsNavigatorContentUtils.h",
     "navigatorcontentutils/testing/NavigatorContentUtilsClientMock.cpp",
     "navigatorcontentutils/testing/NavigatorContentUtilsClientMock.h",
@@ skipping 106 matching lines @@
     ":modules",
     ":modules_testing",
     "//skia",
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/WebKit/Source/core",
     "//third_party/WebKit/Source/wtf",
     "//v8",
   ]
 }