Add class GrGLTextureRenderTarget for GL texture/rendertarget objects

src/gpu/GrContext.cpp

Index: src/gpu/GrContext.cpp
diff --git a/src/gpu/GrContext.cpp b/src/gpu/GrContext.cpp
index 98adf1d667df87ac278de9c3225e17f53fdccfcd..b7674c77f6974caf98b51d5db150e02b6112c2ed 100755
--- a/src/gpu/GrContext.cpp
+++ b/src/gpu/GrContext.cpp
@@ -266,8 +266,12 @@ GrTexture* GrContext::findAndRefTexture(const GrSurfaceDesc& desc,
                                         const GrTextureParams* params) {
     GrResourceKey resourceKey = GrTexturePriv::ComputeKey(fGpu, params, desc, cacheID);
     GrGpuResource* resource = fResourceCache->find(resourceKey);
-    SkSafeRef(resource);
-    return static_cast<GrTexture*>(resource);
+    if (resource) {
+        resource->ref();
+        return static_cast<GrSurface*>(resource)->asTexture();
+    } else {
+        return NULL;
+    }
 }
 
 bool GrContext::isTextureInCache(const GrSurfaceDesc& desc,
@@ -481,7 +485,7 @@ GrTexture* GrContext::refScratchTexture(const GrSurfaceDesc& inDesc, ScratchTexM
             GrGpuResource* resource = fResourceCache2->findAndRefScratchResource(key, scratchFlags);
             if (resource) {
                 fResourceCache->makeResourceMRU(resource);
-                return static_cast<GrTexture*>(resource);
+                return static_cast<GrSurface*>(resource)->asTexture();
             }
 
             if (kExact_ScratchTexMatch == match) {