During virtual context switches only restore texture units that have changed from the previous cont…

gpu/command_buffer/service/context_state.h

Index: gpu/command_buffer/service/context_state.h
diff --git a/gpu/command_buffer/service/context_state.h b/gpu/command_buffer/service/context_state.h
index 8d5edcaea61d08c73810fd60d7c32ea1d2630af9..5fddb13c7bb94ab256d2ae31c1ba29e018c0a527 100644
--- a/gpu/command_buffer/service/context_state.h
+++ b/gpu/command_buffer/service/context_state.h
@@ -98,12 +98,12 @@ struct GPU_EXPORT ContextState {
 
   void Initialize();
 
-  void RestoreState() const;
+  void RestoreState(const ContextState* prev_state) const;
   void InitCapabilities() const;
   void InitState() const;
 
   void RestoreActiveTexture() const;
-  void RestoreAllTextureUnitBindings() const;
+  void RestoreAllTextureUnitBindings(const ContextState* prev_state) const;
   void RestoreAttribute(GLuint index) const;
   void RestoreBufferBindings() const;
   void RestoreGlobalState() const;
@@ -155,6 +155,9 @@ struct GPU_EXPORT ContextState {
   mutable bool fbo_binding_for_scissor_workaround_dirty_;
   FeatureInfo* feature_info_;
 
+  // Maximum active texture unit index in this context.
+  GLuint max_active_texture_unit_;
+
  private:
   scoped_ptr<ErrorState> error_state_;
 };