Index8 GPU and CPU raster support.

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 56 matching lines @@
      *  of this data.
      *
      *  If non-NULL is returned, the caller is responsible for calling
      *  unref() on the data when it is finished.
      */
     SkData* refEncodedData() { return this->onRefEncodedData(); }
 
     /**
      *  Return the ImageInfo associated with this generator.
      */
-    const SkImageInfo& getInfo() const { return fInfo; }
+    const SkImageInfo& getInfo() {
+        SkColorType colorType;
+        if ((colorType = onGetColorType()) != fInfo.colorType())
+            fInfo = fInfo.makeColorType(colorType);
+        return fInfo;
+    }
 
     /**
      *  Decode into the given pixels, a block of memory of size at
      *  least (info.fHeight - 1) * rowBytes + (info.fWidth *
      *  bytesPerPixel)
      *
      *  Repeated calls to this function should give the same results,
      *  allowing the PixelRef to be immutable.
      *
      *  @param info A description of the format (config, size)
@@ skipping 104 matching lines @@
     virtual bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
                              SkPMColor ctable[], int* ctableCount);
     virtual bool onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3]);
     virtual bool onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3],
                                  SkYUVColorSpace* colorSpace);
 
     virtual GrTexture* onGenerateTexture(GrContext*, const SkIRect*) {
         return nullptr;
     }
 
+    virtual SkColorType onGetColorType() { return fInfo.colorType(); }

[aleksandar.stojiljkovic, 2015/12/07 19:31:02]

Does this look better?
Implemented the chromium part here [1], works OK.

[1]
https://codereview.chromium.org/1460523002/diff/100001/third_party/WebKit/Sou...

+
     bool tryGenerateBitmap(SkBitmap* bm, const SkImageInfo* optionalInfo, SkBitmap::Allocator*);
 
 private:
-    const SkImageInfo fInfo;
+    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