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

tools/PictureRenderer.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef PictureRenderer_DEFINED
 #define PictureRenderer_DEFINED
 
@@ skipping 12 matching lines @@
 
 #if SK_SUPPORT_GPU
 #include "GrContextFactory.h"
 #include "GrContext.h"
 #endif
 
 #include "image_expectations.h"
 
 class SkBitmap;
 class SkCanvas;
-class SkGLContext;
+class SkGLContextHelper;
 class SkThread;
 
 namespace sk_tools {
 
 class TiledPictureRenderer;
 
 class PictureRenderer : public SkRefCnt {
 
 public:
     enum SkDeviceTypes {
@@ skipping 318 matching lines @@
 #endif
 #if SK_MESA
             case kMesa_DeviceType:
 #endif
                 return true;
             default:
                 return false;
         }
     }
 
-    SkGLContext* getGLContext() {
+    SkGLContextHelper* getGLContext() {
         GrContextFactory::GLContextType glContextType
                 = GrContextFactory::kNull_GLContextType;
         switch(fDeviceType) {
             case kGPU_DeviceType:
                 glContextType = GrContextFactory::kNative_GLContextType;
                 break;
             case kNVPR_DeviceType:
                 glContextType = GrContextFactory::kNVPR_GLContextType;
                 break;
 #if SK_ANGLE
@@ skipping 330 matching lines @@
 
 #if SK_SUPPORT_GPU
 extern PictureRenderer* CreateGatherPixelRefsRenderer(const GrContext::Options& opts);
 #else
 extern PictureRenderer* CreateGatherPixelRefsRenderer();
 #endif
 
 }
 
 #endif  // PictureRenderer_DEFINED