Add GL State Restoring Functions

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 18e8a368a9c9be0dd1c8f6788a4d2af40d90be79..ef797e3a441b4e09cc7d539d0ff6273e983e19b2 100644
--- a/gpu/command_buffer/service/context_state.h
+++ b/gpu/command_buffer/service/context_state.h
@@ -99,6 +99,14 @@ struct GPU_EXPORT ContextState {
   void InitCapabilities() const;
   void InitState() const;
 
+  void RestoreActiveTexture() const;
+  void RestoreAttribute(GLuint index) const;
+  void RestoreBufferBindings() const;
+  void RestoreGlobalState() const;
+  void RestoreProgramBindings() const;
+  void RestoreRenderbufferBindings() const;
+  void RestoreTextureUnitBindings(GLuint unit) const;
+
   // Helper for getting cached state.
   bool GetStateAsGLint(
       GLenum pname, GLint* params, GLsizei* num_written) const;