Don't copy image buffer when calculating size.

src/core/SkImageCacherator.cpp

 /*
  * Copyright 2015 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 "SkImage_Base.h"
@@ skipping 109 matching lines @@
                                              int srcX, int srcY) {
     ScopedGenerator generator(this);
     const SkImageInfo& genInfo = generator->getInfo();
     // Currently generators do not natively handle subsets, so check that first.
     if (srcX || srcY || genInfo.width() != info.width() || genInfo.height() != info.height()) {
         return false;
     }
     return generator->getPixels(info, pixels, rb);
 }
 
+bool SkImageCacherator::canGenerateTexture(const GrContextThreadSafeProxy& proxy)
+{
+    ScopedGenerator generator(this);
+    return generator->canGenerateTexture(proxy);
+}
+
+
 //////////////////////////////////////////////////////////////////////////////////////////////////
 
 bool SkImageCacherator::lockAsBitmapOnlyIfAlreadyCached(SkBitmap* bitmap) {
     return SkBitmapCache::Find(fUniqueID, bitmap) && check_output_bitmap(*bitmap, fUniqueID);
 }
 
 bool SkImageCacherator::tryLockAsBitmap(SkBitmap* bitmap, const SkImage* client,
                                         SkImage::CachingHint chint) {
     if (this->lockAsBitmapOnlyIfAlreadyCached(bitmap)) {
         return true;
@@ skipping 207 matching lines @@
 
 #else
 
 GrTexture* SkImageCacherator::lockAsTexture(GrContext* ctx, const GrTextureParams&,
                                             SkSourceGammaTreatment gammaTreatment,
                                             const SkImage* client, SkImage::CachingHint) {
     return nullptr;
 }
 
 #endif