gpu: Extract the gpu timing code from gpu_tracer.

gpu/command_buffer/service/gpu_service_test.h

Index: gpu/command_buffer/service/gpu_service_test.h
diff --git a/gpu/command_buffer/service/gpu_service_test.h b/gpu/command_buffer/service/gpu_service_test.h
index 539d6ba7f3fefa811401a35f09f020041ab80ad4..7c9c9782f323ad7a7f26e8b8391f06e9bc0fb707 100644
--- a/gpu/command_buffer/service/gpu_service_test.h
+++ b/gpu/command_buffer/service/gpu_service_test.h
@@ -28,6 +28,7 @@ class GpuServiceTest : public testing::Test {
   void SetUpWithGLVersion(const char* gl_version, const char* gl_extensions);
   void SetUp() override;
   void TearDown() override;
+  gfx::GLContext* GetGLContext();
 
   scoped_ptr< ::testing::StrictMock< ::gfx::MockGLInterface> > gl_;
 
@@ -40,4 +41,4 @@ class GpuServiceTest : public testing::Test {
 }  // namespace gles2
 }  // namespace gpu
 
-#endif  // GPU_COMMAND_BUFFER_SERVICE_MAILBOX_SYNCHRONIZER_H_
+#endif  // GPU_COMMAND_BUFFER_SERVICE_GPU_SERVICE_TEST_H_