Fix GN linking issues.

mojo/mojo.gyp

 # Copyright 2013 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.
 
 {
   'target_defaults': {
     'conditions': [
       ['mojo_shell_debug_url != ""', {
         'defines': [
           'MOJO_SHELL_DEBUG=1',
@@ skipping 702 matching lines @@
         'mojo_service_manager',
         'mojo_application',
       ],
       'includes': [ 'public/tools/bindings/mojom_bindings_generator.gypi' ],
       'sources': [
         'service_manager/service_manager_unittest.cc',
         'service_manager/test.mojom',
       ],
     },
     {
+      # GN version: //mojo/bindings/js
       'target_name': 'mojo_js_bindings_lib',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
         '../gin/gin.gyp:gin',
         '../v8/tools/gyp/v8.gyp:v8',
         'mojo_common_lib',
       ],
       'export_dependent_settings': [
         '../base/base.gyp:base',
         '../gin/gin.gyp:gin',
         'mojo_common_lib',
       ],
       'sources': [
+        # Sources list duplicated in GN build.
         'bindings/js/core.cc',
         'bindings/js/core.h',
         'bindings/js/handle.cc',
         'bindings/js/handle.h',
         'bindings/js/support.cc',
         'bindings/js/support.h',
         'bindings/js/waiting_callback.cc',
         'bindings/js/waiting_callback.h',
       ],
     },
@@ skipping 307 matching lines @@
             'views/views_init_internal.h',
           ],
           'defines': [
             'MOJO_VIEWS_IMPLEMENTATION',
           ],
         },
       ],
     }],
   ],
 }