Renamed ChannelObserver to better describe its purpose

ui/ozone/platform/drm/gbm.gypi

 # 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': {
     'internal_ozone_platform_deps': [
       'ozone_platform_gbm',
     ],
     'internal_ozone_platform_unittest_deps': [
@@ skipping 103 matching lines @@
         'gpu/hardware_display_plane_manager_legacy.cc',
         'gpu/hardware_display_plane_manager_legacy.h',
         'gpu/overlay_plane.cc',
         'gpu/overlay_plane.h',
         'gpu/page_flip_request.cc',
         'gpu/page_flip_request.h',
         'gpu/proxy_helpers.cc',
         'gpu/proxy_helpers.h',
         'gpu/screen_manager.cc',
         'gpu/screen_manager.h',
-        'host/channel_observer.h',
         'host/drm_cursor.cc',
         'host/drm_cursor.h',
         'host/drm_cursor_core.cc',
         'host/drm_cursor_core.h',
         'host/drm_device_handle.cc',
         'host/drm_device_handle.h',
         'host/drm_display_host.cc',
         'host/drm_display_host.h',
         'host/drm_display_host_manager.cc',
         'host/drm_display_host_manager.h',
         'host/drm_display_host_manager_core.cc',
         'host/drm_display_host_manager_core.h',
         'host/drm_gpu_platform_support_host.cc',
         'host/drm_gpu_platform_support_host.h',
         'host/drm_native_display_delegate.cc',
         'host/drm_native_display_delegate.h',
         'host/drm_overlay_candidates_host.cc',
         'host/drm_overlay_candidates_host.h',
         'host/drm_overlay_manager_core.cc',
         'host/drm_overlay_manager_core.h',
         'host/drm_overlay_manager.cc',
         'host/drm_overlay_manager.h',
         'host/drm_window_host.cc',
         'host/drm_window_host.h',
         'host/drm_window_host_manager.cc',
         'host/drm_window_host_manager.h',
+        'host/gpu_thread_observer.h',
         'ozone_platform_gbm.cc',
         'ozone_platform_gbm.h',
       ],
       'conditions': [
         ['use_vgem_map==1', {
           'dependencies': [
             '../ozone/ozone.gyp:vgem_map',
           ],
           'sources': [
             'common/client_native_pixmap_vgem.cc',
@@ skipping 44 matching lines @@
           'gpu/mock_scanout_buffer.cc',
           'gpu/mock_scanout_buffer.h',
           'gpu/mock_scanout_buffer_generator.cc',
           'gpu/mock_scanout_buffer_generator.h',
           'gpu/screen_manager_unittest.cc',
         ],
       },
     },
   ],
 }