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..e3fa332dcaeb96151d6fc8dff4e809fb84e901c9 100644
--- a/gpu/command_buffer/service/gpu_tracer.h
+++ b/gpu/command_buffer/service/gpu_tracer.h
@@ -73,8 +73,8 @@ 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:
   // Trace Processing.
@@ -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();