Refactored GLContext to own GPUTiming which spawn GPUTimingClients.

gpu/command_buffer/service/gpu_tracer.h

Index: gpu/command_buffer/service/gpu_tracer.h
diff --git a/gpu/command_buffer/service/gpu_tracer.h b/gpu/command_buffer/service/gpu_tracer.h
index 7aba61271b2f835cb43fb828ef4c812f6159737c..270a18754bd2ca4f38ea347a2eaec5f9afad9f65 100644
--- a/gpu/command_buffer/service/gpu_tracer.h
+++ b/gpu/command_buffer/service/gpu_tracer.h
@@ -15,10 +15,15 @@
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
-#include "gpu/command_buffer/service/gpu_timing.h"
 #include "gpu/gpu_export.h"
 
 namespace gpu {
+  class GPUTiming;
+  class GPUTimingClient;
+  class GPUTimer;
+}
+
+namespace gpu {
 namespace gles2 {
 
 class Outputter;
@@ -82,6 +87,7 @@ class GPU_EXPORT GPUTracer
 
   void IssueProcessTask();
 
+  scoped_refptr<GPUTimingClient> gpu_timing_client_;
   scoped_refptr<Outputter> outputter_;
   std::vector<TraceMarker> markers_[NUM_TRACER_SOURCES];
   std::deque<scoped_refptr<GPUTrace> > traces_;
@@ -89,7 +95,6 @@ class GPU_EXPORT GPUTracer
   const unsigned char* gpu_trace_srv_category;
   const unsigned char* gpu_trace_dev_category;
   gles2::GLES2Decoder* decoder_;
-  gpu::GPUTiming gpu_timing_;
 
   bool gpu_executing_;
   bool process_posted_;
@@ -146,7 +151,7 @@ class GPU_EXPORT GPUTrace
     : public base::RefCounted<GPUTrace> {
  public:
   GPUTrace(scoped_refptr<Outputter> outputter,
-           gpu::GPUTiming* gpu_timing,
+           GPUTimingClient* gpu_timing_client,
            const std::string& category,
            const std::string& name,
            const bool enabled);