Add wrapBackendTextureAsRenderTarget API

src/gpu/GrTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrTest.h"
 
 #include "GrBatchAtlas.h"
@@ skipping 321 matching lines @@
     }
 
     GrTexture* onWrapBackendTexture(const GrBackendTextureDesc&,
                                     GrWrapOwnership) override { return nullptr; }
 
     GrRenderTarget* onWrapBackendRenderTarget(const GrBackendRenderTargetDesc&,
                                               GrWrapOwnership) override {
         return nullptr;
     }
 
+    GrRenderTarget* onWrapBackendTextureAsRenderTarget(const GrBackendTextureDesc&,
+                                                       GrWrapOwnership) override {
+        return nullptr;
+    }
+
     GrVertexBuffer* onCreateVertexBuffer(size_t size, bool dynamic) override { return nullptr; }
 
     GrIndexBuffer* onCreateIndexBuffer(size_t size, bool dynamic) override { return nullptr; }
 
     GrTransferBuffer* onCreateTransferBuffer(size_t, TransferType) override { return nullptr; }
 
     void onClear(GrRenderTarget*, const SkIRect& rect, GrColor color) override {}
 
     void onClearStencilClip(GrRenderTarget*, const SkIRect& rect, bool insideClip) override {}
 
@@ skipping 54 matching lines @@
     SkASSERT(nullptr == fGpu);
     fGpu = new MockGpu(this, options);
     SkASSERT(fGpu);
     this->initCommon(options);
 
     // We delete these because we want to test the cache starting with zero resources. Also, none of
     // these objects are required for any of tests that use this context. TODO: make stop allocating
     // resources in the buffer pools.
     fDrawingManager->abandon();
 }