Add isEncoded to SkImageGenerator

include/core/SkImageGenerator.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageGenerator_DEFINED
 #define SkImageGenerator_DEFINED
 
@@ skipping 52 matching lines @@
 public:
     /**
      *  The PixelRef which takes ownership of this SkImageGenerator
      *  will call the image generator's destructor.
      */
     virtual ~SkImageGenerator() { }
 
     uint32_t uniqueID() const { return fUniqueID; }
 
     /**
+     * Returns true if the image is encoded (i.e. compressed).
+     */
+    bool isEncoded() const { return this->onIsEncoded(); }

[cblume, 2016/10/20 19:08:39]

Note that this is adding a function to the public API.
I know we would prefer to change the public API as little as possible. If there
is a better alternative I'm happy to do that.

+
+    /**
      *  Return a ref to the encoded (i.e. compressed) representation,
      *  of this data. If the GrContext is non-null, then the caller is only interested in
      *  gpu-specific formats, so the impl may return null even if they have encoded data,
      *  assuming they know it is not suitable for the gpu.
      *
      *  If non-NULL is returned, the caller is responsible for calling
      *  unref() on the data when it is finished.
      */
     SkData* refEncodedData(GrContext* ctx = nullptr) {
 #ifdef SK_SUPPORT_LEGACY_REFENCODEDDATA_NOCTX
@@ skipping 167 matching lines @@
         }
     }
 
 protected:
     enum {
         kNeedNewImageUniqueID = 0
     };
 
     SkImageGenerator(const SkImageInfo& info, uint32_t uniqueId = kNeedNewImageUniqueID);
 
+    virtual bool onIsEncoded() const;
+
     virtual SkData* onRefEncodedData(SK_REFENCODEDDATA_CTXPARAM);
 
     virtual bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
                              SkPMColor ctable[], int* ctableCount);
 
     virtual bool onQueryYUV8(SkYUVSizeInfo*, SkYUVColorSpace*) const {
         return false;
     }
     virtual bool onGetYUV8Planes(const SkYUVSizeInfo&, void*[3] /*planes*/) {
         return false;
@@ skipping 16 matching lines @@
     const SkImageInfo fInfo;
     const uint32_t fUniqueID;
 
     // This is our default impl, which may be different on different platforms.
     // It is called from NewFromEncoded() after it has checked for any runtime factory.
     // The SkData will never be NULL, as that will have been checked by NewFromEncoded.
     static SkImageGenerator* NewFromEncodedImpl(SkData*);
 };
 
 #endif  // SkImageGenerator_DEFINED