Revert of Make the Sk GL context class an abstract base class

include/gpu/gl/SkMesaGLContext.h

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkMesaGLContext_DEFINED
 #define SkMesaGLContext_DEFINED
 
-#include "SkGLContext.h"
+#include "SkGLContextHelper.h"
 
 #if SK_MESA
 
-class SkMesaGLContext : public SkGLContext {
+class SkMesaGLContext : public SkGLContextHelper {
 private:
     typedef intptr_t Context;
 
 public:
     SkMesaGLContext();
 
     virtual ~SkMesaGLContext();
 
     virtual void makeCurrent() const SK_OVERRIDE;
     virtual void swapBuffers() const SK_OVERRIDE;
 
+    class AutoContextRestore {
+    public:
+        AutoContextRestore();
+        ~AutoContextRestore();
+
+    private:
+        Context fOldContext;
+        GrGLint fOldWidth;
+        GrGLint fOldHeight;
+        GrGLint fOldFormat;
+        void*   fOldImage;
+    };
+
 protected:
     virtual const GrGLInterface* createGLContext(GrGLStandard forcedGpuAPI) SK_OVERRIDE;
     virtual void destroyGLContext() SK_OVERRIDE;
 
 private:
     Context fContext;
     GrGLubyte *fImage;
 };
 
 #endif
 
 #endif