gpu: Fix some context lost marking glitches+leaks and add UMA stats

gpu/command_buffer/service/gles2_cmd_decoder.h

Index: gpu/command_buffer/service/gles2_cmd_decoder.h
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.h b/gpu/command_buffer/service/gles2_cmd_decoder.h
index 0cbe0fe586dd6feb095c0268952f1b01c2bd34f1..ac01c95804cc0a2dcd1d30864915d422a91e937a 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.h
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.h
@@ -241,13 +241,13 @@ class GPU_EXPORT GLES2Decoder : public base::SupportsWeakPtr<GLES2Decoder>,
 
   // Returns true if the context was lost either by GL_ARB_robustness, forced
   // context loss or command buffer parse error.
-  virtual bool WasContextLost() = 0;
+  virtual bool WasContextLost() const = 0;
 
   // Returns true if the context was lost specifically by GL_ARB_robustness.
-  virtual bool WasContextLostByRobustnessExtension() = 0;
+  virtual bool WasContextLostByRobustnessExtension() const = 0;
 
   // Lose this context.
-  virtual void LoseContext(uint32 reset_status) = 0;
+  virtual void MarkContextLost(error::ContextLostReason reason) = 0;
 
   virtual Logger* GetLogger() = 0;