take gr-context parameter to refEncoded, indicating a desire for only gpu-specific formats

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 184 matching lines @@
     SkBitmap bm;
     SkAutoPixmapUnlock apu;
     if (as_IB(this)->getROPixels(&bm) && bm.requestLock(&apu)) {
         return effectiveSerializer->encode(apu.pixmap());
     }
 
     return nullptr;
 }
 
 SkData* SkImage::refEncoded() const {
-    return as_IB(this)->onRefEncoded();
+    GrContext* ctx = nullptr;   // should we allow the caller to pass in a ctx?
+    return as_IB(this)->onRefEncoded(ctx);
 }
 
 SkImage* SkImage::NewFromEncoded(SkData* encoded, const SkIRect* subset) {
     if (nullptr == encoded || 0 == encoded->size()) {
         return nullptr;
     }
     SkImageGenerator* generator = SkImageGenerator::NewFromEncoded(encoded);
     return generator ? SkImage::NewFromGenerator(generator, subset) : nullptr;
 }
 
@@ skipping 190 matching lines @@
 
 SkImage* SkImage::NewFromAdoptedTexture(GrContext*, const GrBackendTextureDesc&, SkAlphaType) {
     return nullptr;
 }
 
 SkImage* SkImage::NewFromTextureCopy(GrContext*, const GrBackendTextureDesc&, SkAlphaType) {
     return nullptr;
 }
 
 #endif