Add whitelist parameter to refEncodedData

src/core/SkImageCacherator.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageCacherator_DEFINED
 #define SkImageCacherator_DEFINED
 
+#include "SkImage.h"
 #include "SkImageGenerator.h"
 #include "SkMutex.h"
 #include "SkTemplates.h"
 
 class GrContext;
 class GrTextureParams;
 class GrUniqueKey;
 class SkBitmap;
 class SkImage;
 
@@ skipping 73 matching lines @@
     SkMutex                         fMutexForGenerator;
     SkAutoTDelete<SkImageGenerator> fNotThreadSafeGenerator;
 
     const SkImageInfo   fInfo;
     const SkIPoint      fOrigin;
     const uint32_t      fUniqueID;
 
     friend class GrImageTextureMaker;
 };
 
+// Exposed so it can be tested, not meant for external usage per-se
+//
+class SkGpuFormatWhitelist : public SkImageGenerator::RefEncodedWhitelist {
+    GrContext* fCtx;
+public:
+    SkGpuFormatWhitelist(GrContext* ctx) : fCtx(ctx) {}
+
+    bool includes(SkEncodedFormat format) override;
+};
+
 #endif