Added disjoint context class which manages disjoints within gpu timing.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index f530974de0582ed0aa9ea9b7ede3ed8020854a5e..c6e3132ad765123a27b2c2d07750cad324cf131c 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -46,6 +46,7 @@
 #include "gpu/command_buffer/service/gles2_cmd_validation.h"
 #include "gpu/command_buffer/service/gpu_state_tracer.h"
 #include "gpu/command_buffer/service/gpu_switches.h"
+#include "gpu/command_buffer/service/gpu_timing.h"
 #include "gpu/command_buffer/service/gpu_tracer.h"
 #include "gpu/command_buffer/service/image_manager.h"
 #include "gpu/command_buffer/service/mailbox_manager.h"
@@ -1882,6 +1883,7 @@ class GLES2DecoderImpl : public GLES2Decoder,
   DecoderTextureState texture_state_;
   DecoderFramebufferState framebuffer_state_;
 
+  GPUTiming gpu_timing_;
   scoped_ptr<GPUTracer> gpu_tracer_;
   scoped_ptr<GPUStateTracer> gpu_state_tracer_;
   const unsigned char* cb_command_trace_category_;
@@ -2445,7 +2447,7 @@ bool GLES2DecoderImpl::Initialize(
   surfaceless_ = surface->IsSurfaceless() && !offscreen;
 
   set_initialized();
-  gpu_tracer_.reset(new GPUTracer(this));
+  gpu_tracer_.reset(new GPUTracer(this, &gpu_timing_));
   gpu_state_tracer_ = GPUStateTracer::Create(&state_);
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(