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

gpu/gpu.gyp

 # 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.
 
 {
   'variables': {
     'nacl_win64_target': 0,
   },
   'includes': [
     'gpu_common.gypi',
@@ skipping 187 matching lines @@
         'command_buffer/service/async_pixel_transfer_delegate_mock.h',
         'command_buffer/service/async_pixel_transfer_manager_mock.cc',
         'command_buffer/service/async_pixel_transfer_manager_mock.h',
         'command_buffer/service/buffer_manager_unittest.cc',
         'command_buffer/service/cmd_parser_test.cc',
         'command_buffer/service/command_buffer_service_unittest.cc',
         'command_buffer/service/common_decoder_unittest.cc',
         'command_buffer/service/context_group_unittest.cc',
         'command_buffer/service/feature_info_unittest.cc',
         'command_buffer/service/framebuffer_manager_unittest.cc',
+        'command_buffer/service/gl_context_mock.cc',
+        'command_buffer/service/gl_context_mock.h',
         'command_buffer/service/gl_surface_mock.cc',
         'command_buffer/service/gl_surface_mock.h',
         'command_buffer/service/gles2_cmd_decoder_unittest.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest.h',
         'command_buffer/service/gles2_cmd_decoder_unittest_0_autogen.h',
         'command_buffer/service/gles2_cmd_decoder_unittest_1.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_1_autogen.h',
         'command_buffer/service/gles2_cmd_decoder_unittest_2.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_2_autogen.h',
         'command_buffer/service/gles2_cmd_decoder_unittest_3.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_3_autogen.h',
         'command_buffer/service/gles2_cmd_decoder_unittest_async_pixel.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_attribs.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_base.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_base.h',
         'command_buffer/service/gles2_cmd_decoder_unittest_buffers.cc',
+        'command_buffer/service/gles2_cmd_decoder_unittest_context_lost.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_context_state.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_drawing.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_extensions.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_extensions_autogen.h',
         'command_buffer/service/gles2_cmd_decoder_unittest_framebuffers.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_programs.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_textures.cc',
         'command_buffer/service/gles2_cmd_decoder_unittest_valuebuffer.cc',
         'command_buffer/service/gpu_scheduler_unittest.cc',
         'command_buffer/service/gpu_service_test.cc',
@@ skipping 514 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'gpu_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }