Add a function to convert a texture backed SkImage to raster.

src/image/SkImage.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkBitmapCache.h"
 #include "SkCanvas.h"
@@ skipping 413 matching lines @@
                                                 const GrBackendObject yuvTextureHandles[3],
                                                 const SkISize yuvSizes[3],
                                                 GrSurfaceOrigin origin) {
     return nullptr;
 }
 
 sk_sp<SkImage> SkImage::makeTextureImage(GrContext*) const {
     return nullptr;
 }
 
+sk_sp<SkImage> SkImage::makeNonTextureImage() const {
+    return sk_ref_sp(const_cast<SkImage*>(this));
+}
+
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 #ifdef SK_SUPPORT_LEGACY_IMAGEFACTORY
 SkImage* SkImage::NewRasterCopy(const Info& info, const void* pixels, size_t rowBytes,
                                 SkColorTable* ctable) {
     return MakeRasterCopy(SkPixmap(info, pixels, rowBytes, ctable)).release();
 }
 
@@ skipping 53 matching lines @@
 SkImage* SkImage::NewFromDeferredTextureImageData(GrContext* ctx, const void* data,
                                                   SkBudgeted budgeted) {
     return MakeFromDeferredTextureImageData(ctx, data, budgeted).release();
 }
 #endif
 
 sk_sp<SkImage> MakeTextureFromMipMap(GrContext*, const SkImageInfo&, const GrMipLevel* texels,
                                      int mipLevelCount, SkBudgeted) {
     return nullptr;
 }