Add class GrGLTextureRenderTarget for GL texture/rendertarget objects

src/effects/SkColorCubeFilter.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorCubeFilter.h"
 #include "SkColorPriv.h"
 #include "SkOnce.h"
@@ skipping 338 matching lines @@
     key.fData32[0] = fUniqueID;
     key.fData32[1] = fCache.cubeDimension();
     key.fData64[1] = 0;
     GrCacheID cacheID(gCubeDomain, key);
 
     GrSurfaceDesc desc;
     desc.fWidth = fCache.cubeDimension();
     desc.fHeight = fCache.cubeDimension() * fCache.cubeDimension();
     desc.fConfig = kRGBA_8888_GrPixelConfig;
 
-    SkAutoTUnref<GrTexture> textureCube(
-        static_cast<GrTexture*>(context->findAndRefCachedResource(
-            GrTexturePriv::ComputeKey(context->getGpu(), NULL, desc, cacheID))));
-
-    if (!textureCube) {
+    GrResourceKey rkey = GrTexturePriv::ComputeKey(context->getGpu(), NULL, desc, cacheID);
+    GrSurface* surface = static_cast<GrSurface*>(context->findAndRefCachedResource(rkey));
+    SkAutoTUnref<GrTexture> textureCube;
+    if (surface) {
+        textureCube.reset(surface->asTexture());
+    } else {
         textureCube.reset(context->createTexture(NULL, desc, cacheID, fCubeData->data(), 0));
     }
 
     return textureCube ? GrColorCubeEffect::Create(textureCube) : NULL;
 }
 #endif