Block internal PlatformEvents before they are dispatched in touchview.

ui/events/platform/events_platform.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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [{
     'target_name': 'events_platform',
     'type': '<(component)',
     'dependencies': [
       '../../../base/base.gyp:base',
     ],
     'defines': [
       'EVENTS_IMPLEMENTATION',
     ],
     'sources': [
       'platform_event_dispatcher.h',
+      'platform_event_filter.h',
       'platform_event_observer.h',
       'platform_event_source.cc',
       'platform_event_source.h',
       'platform_event_source_stub.cc',
       'platform_event_types.h',
       'scoped_event_dispatcher.cc',
       'scoped_event_dispatcher.h',
     ],
     'conditions': [
       ['use_x11==1', {
         'sources!': [
           'platform_event_source_stub.cc',
         ],
       }],
     ],
   }],
 }