Fixed GPU tracing so the categories do not get mixed.

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 603322079c18e883a00f0787a4b9bf128f70e7bc..8c1f61be6f6d0cfe0c9b571c7e423cb9fbd533ae 100644
--- a/gpu/command_buffer/service/gpu_tracer.h
+++ b/gpu/command_buffer/service/gpu_tracer.h
@@ -51,7 +51,8 @@ struct TraceMarker {
 };
 
 // Traces GPU Commands.
-class GPUTracer : public base::SupportsWeakPtr<GPUTracer> {
+class GPU_EXPORT GPUTracer
+    : public base::SupportsWeakPtr<GPUTracer> {
  public:
   explicit GPUTracer(gles2::GLES2Decoder* decoder);
   ~GPUTracer();
@@ -73,10 +74,10 @@ class GPUTracer : public base::SupportsWeakPtr<GPUTracer> {
 
   // Retrieve the name of the current open trace.
   // Returns empty string if no current open trace.
-  const std::string& CurrentCategory() const;
-  const std::string& CurrentName() const;
+  const std::string& CurrentCategory(GpuTracerSource source) const;
+  const std::string& CurrentName(GpuTracerSource source) const;
 
- private:
+ protected:
   // Trace Processing.
   scoped_refptr<GPUTrace> CreateTrace(const std::string& category,
                                       const std::string& name);
@@ -95,7 +96,6 @@ class GPUTracer : public base::SupportsWeakPtr<GPUTracer> {
   gles2::GLES2Decoder* decoder_;
 
   int64 timer_offset_;
-  GpuTracerSource last_tracer_source_;
 
   GpuTracerType tracer_type_;
   bool gpu_timing_synced_;
@@ -147,11 +147,8 @@ class GPU_EXPORT GPUTrace
 
   bool IsEnabled() { return tracer_type_ != kTracerTypeInvalid; }
 
-  const std::string& category() { return category_; }
-  const std::string& name() { return name_; }
-
   void Start(bool trace_service);
-  void End(bool tracing_service);
+  void End(bool trace_service);
   bool IsAvailable();
   void Process();