Make HandleWatcher watch on the same thread if the thread is running a MessagePumpMojo.

mojo/mojo_base.gyp

 # 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.
 
 # Essential components (and their tests) that are needed to build
 # Chrome should be here.  Other components that are useful only in
 # Mojo land like mojo_shell should be in mojo.gyp.
 {
   'includes': [
     'mojo_public.gypi',
@@ skipping 407 matching lines @@
     {
      # GN version: //mojo/public/cpp/application:chromium
      'target_name': 'mojo_application_chromium',
      'type': 'static_library',
      'sources': [
        'public/cpp/application/lib/application_runner_chromium.cc',
        'public/cpp/application/application_runner_chromium.h',
       ],
       'dependencies': [
         'mojo_application_base',
+        'mojo_common_lib',
         'mojo_environment_chromium',
        ],
       'export_dependent_settings': [
         'mojo_application_base',
        ],
     },
     {
       # GN version: //mojo/bindings/js
       'target_name': 'mojo_js_bindings_lib',
       'type': 'static_library',
@@ skipping 151 matching lines @@
             'mojo_js_unittests.isolate',
           ],
           'sources': [
             'mojo_js_unittests.isolate',
           ],
         },
       ],
     }],
   ]
 }