Add ability to extract YUV planes from SkImage

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 240 matching lines @@
         }
         return true;
     }
     return false;
 }
 
 bool SkImage::readPixels(const SkPixmap& pmap, int srcX, int srcY, CachingHint chint) const {
     return this->readPixels(pmap.info(), pmap.writable_addr(), pmap.rowBytes(), srcX, srcY, chint);
 }
 
+#if SK_SUPPORT_GPU
+#include "GrTextureToYUVPlanes.h"
+#endif
+
+#include "SkRGBAToYUV.h"
+
+bool SkImage::readYUV8Planes(const SkISize sizes[3], void* const planes[3],
+                             const size_t rowBytes[3], SkYUVColorSpace colorSpace) {
+#if SK_SUPPORT_GPU
+    if (GrTexture* texture = as_IB(this)->peekTexture()) {
+        if (GrTextureToYUVPlanes(texture, sizes, planes, rowBytes, colorSpace)) {
+            return true;
+        }
+    }
+#endif
+    return SkRGBAToYUV(this, sizes, planes, rowBytes, colorSpace);
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 SkImage* SkImage::NewFromBitmap(const SkBitmap& bm) {
     SkPixelRef* pr = bm.pixelRef();
     if (nullptr == pr) {
         return nullptr;
     }
 
 #if SK_SUPPORT_GPU
     if (GrTexture* tex = pr->getTexture()) {
@@ skipping 66 matching lines @@
 
 SkImage* SkImage::NewFromTextureCopy(GrContext*, const GrBackendTextureDesc&, SkAlphaType) {
     return nullptr;
 }
 
 SkImage* SkImage::newTextureImage(GrContext*) const {
     return nullptr;
 }
 
 #endif