Added disjoint context class which manages disjoints within gpu timing.

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..8f4aeb28a7aab7456452689c21e553a7aaadeb57 100644
--- a/gpu/command_buffer/service/gpu_tracer.h
+++ b/gpu/command_buffer/service/gpu_tracer.h
@@ -49,7 +49,7 @@ struct TraceMarker {
 class GPU_EXPORT GPUTracer
     : public base::SupportsWeakPtr<GPUTracer> {
  public:
-  explicit GPUTracer(gles2::GLES2Decoder* decoder);
+  GPUTracer(gles2::GLES2Decoder* decoder, GPUTiming* gpu_timing);
   virtual ~GPUTracer();
 
   // Scheduled processing in decoder begins.
@@ -89,7 +89,8 @@ 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_;
+  GPUTiming* gpu_timing_;
+  int disjoint_context_id_;
 
   bool gpu_executing_;
   bool process_posted_;
@@ -146,7 +147,7 @@ class GPU_EXPORT GPUTrace
     : public base::RefCounted<GPUTrace> {
  public:
   GPUTrace(scoped_refptr<Outputter> outputter,
-           gpu::GPUTiming* gpu_timing,
+           GPUTiming* gpu_timing,
            const std::string& category,
            const std::string& name,
            const bool enabled);