gpu: Fix some context lost marking glitches+leaks and add UMA stats

content/content_common.gypi

 # Copyright (c) 2012 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../components/tracing.gyp:tracing',
     '../gpu/command_buffer/command_buffer.gyp:gles2_utils',
     '../net/net.gyp:net',
@@ skipping 249 matching lines @@
       'common/gamepad_param_traits.cc',
       'common/gamepad_param_traits.h',
       'common/gamepad_user_gesture.cc',
       'common/gamepad_user_gesture.h',
       'common/geofencing_messages.h',
       'common/geofencing_types.cc',
       'common/geofencing_types.h',
       'common/gin_java_bridge_messages.h',
       'common/gpu/client/command_buffer_proxy_impl.cc',
       'common/gpu/client/command_buffer_proxy_impl.h',
+      'common/gpu/client/command_buffer_metrics.cc',
+      'common/gpu/client/command_buffer_metrics.h',
       'common/gpu/client/context_provider_command_buffer.cc',
       'common/gpu/client/context_provider_command_buffer.h',
       'common/gpu/client/gl_helper.cc',
       'common/gpu/client/gl_helper.h',
       'common/gpu/client/gl_helper_readback_support.cc',
       'common/gpu/client/gl_helper_readback_support.h',
       'common/gpu/client/gl_helper_scaling.cc',
       'common/gpu/client/gl_helper_scaling.h',
       'common/gpu/client/gpu_channel_host.cc',
       'common/gpu/client/gpu_channel_host.h',
@@ skipping 769 matching lines @@
         'common/gpu/client/gpu_memory_buffer_impl_ozone.cc',
         'common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.cc',
         'common/gpu/client/gpu_memory_buffer_impl_ozone_native_buffer.h',
         'common/gpu/gpu_memory_buffer_factory_ozone.cc',
         'common/gpu/gpu_memory_buffer_factory_ozone_native_buffer.cc',
         'common/gpu/gpu_memory_buffer_factory_ozone_native_buffer.h',
       ],
     }],
   ],
 }