Move functions from SkGr to SkGrPriv.h

example/HelloWorld.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  */
 
 #include "HelloWorld.h"
 
 #include "gl/GrGLInterface.h"
+#include "GrContext.h"
 #include "SkApplication.h"
 #include "SkCanvas.h"
 #include "SkGradientShader.h"
 #include "SkGraphics.h"
 #include "SkGr.h"
 
 void application_init() {
     SkGraphics::Init();
     SkEvent::Init();
 }
@@ skipping 160 matching lines @@
         setUpBackend();
         this->setTitle();
         this->inval(NULL);
     }
     return true;
 }
 
 SkOSWindow* create_sk_window(void* hwnd, int , char** ) {
     return new HelloWorldWindow(hwnd);
 }