Added disjoint context class which manages disjoints within gpu timing.

gpu/command_buffer/service/gpu_tracer.cc

Index: gpu/command_buffer/service/gpu_tracer.cc
diff --git a/gpu/command_buffer/service/gpu_tracer.cc b/gpu/command_buffer/service/gpu_tracer.cc
index cc484dc36f58d24a831618a01ce10676aec5e53f..96a04cb8ddab4b3449c1c04554a328c185a19719 100644
--- a/gpu/command_buffer/service/gpu_tracer.cc
+++ b/gpu/command_buffer/service/gpu_tracer.cc
@@ -81,7 +81,7 @@ void TraceOutputter::TraceServiceEnd(const std::string& category,
 }
 
 GPUTrace::GPUTrace(scoped_refptr<Outputter> outputter,
-                   gpu::GPUTiming* gpu_timing,
+                   GPUTiming* gpu_timing,
                    const std::string& category,
                    const std::string& name,
                    const bool enabled)
@@ -130,15 +130,18 @@ void GPUTrace::Process() {
   }
 }
 
-GPUTracer::GPUTracer(gles2::GLES2Decoder* decoder)
+GPUTracer::GPUTracer(gles2::GLES2Decoder* decoder, GPUTiming* gpu_timing)
     : gpu_trace_srv_category(TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(
           TRACE_DISABLED_BY_DEFAULT("gpu.service"))),
       gpu_trace_dev_category(TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(
           TRACE_DISABLED_BY_DEFAULT("gpu.device"))),
       decoder_(decoder),
-      gpu_timing_(),
+      gpu_timing_(gpu_timing),
+      disjoint_context_id_(gpu_timing->CreateDisjointContextID()),
       gpu_executing_(false),
       process_posted_(false) {
+  DCHECK(decoder);
+  DCHECK(gpu_timing);
 }
 
 GPUTracer::~GPUTracer() {
@@ -149,24 +152,23 @@ bool GPUTracer::BeginDecoding() {
     return false;
 
   if (outputter_ == NULL) {
-    outputter_ = CreateOutputter(gpu_timing_.GetTimerTypeName());
-    gpu_timing_.Initialize(decoder_->GetGLContext());
+    outputter_ = CreateOutputter(gpu_timing_->GetTimerTypeName());
   }
 
   if (*gpu_trace_dev_category == '\0') {
     // If GPU device category is off, invalidate timing sync.
-    gpu_timing_.InvalidateTimerOffset();
+    gpu_timing_->InvalidateTimerOffset();
   }
 
   gpu_executing_ = true;
   if (IsTracing()) {
-    gpu_timing_.CheckAndResetTimerErrors();
+    gpu_timing_->CheckAndResetTimerErrors(disjoint_context_id_);
     // Begin a Trace for all active markers
     for (int n = 0; n < NUM_TRACER_SOURCES; n++) {
       for (size_t i = 0; i < markers_[n].size(); i++) {
         TraceMarker& trace_marker = markers_[n][i];
         trace_marker.trace_ =
-            new GPUTrace(outputter_, &gpu_timing_, trace_marker.category_,
+            new GPUTrace(outputter_, gpu_timing_, trace_marker.category_,
                          trace_marker.name_, *gpu_trace_dev_category != 0);
         trace_marker.trace_->Start(*gpu_trace_srv_category != 0);
       }
@@ -216,7 +218,7 @@ bool GPUTracer::Begin(const std::string& category, const std::string& name,
   // Create trace
   if (IsTracing()) {
     scoped_refptr<GPUTrace> trace = new GPUTrace(
-        outputter_, &gpu_timing_, category, name, *gpu_trace_dev_category != 0);
+        outputter_, gpu_timing_, category, name, *gpu_trace_dev_category != 0);
     trace->Start(*gpu_trace_srv_category != 0);
     markers_[source].back().trace_ = trace;
   }
@@ -288,7 +290,7 @@ void GPUTracer::Process() {
 }
 
 void GPUTracer::ProcessTraces() {
-  if (!gpu_timing_.IsAvailable()) {
+  if (!gpu_timing_->IsAvailable()) {
     traces_.clear();
     return;
   }
@@ -304,7 +306,7 @@ void GPUTracer::ProcessTraces() {
 
   // Check if timers are still valid (e.g: a disjoint operation
   // might have occurred.)
-  if (gpu_timing_.CheckAndResetTimerErrors())
+  if (gpu_timing_->CheckAndResetTimerErrors(disjoint_context_id_))
     traces_.clear();
 
   while (!traces_.empty() && traces_.front()->IsAvailable()) {