Make BitmapRegionDecoder succeed on invalid requests

include/codec/SkAndroidCodec.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 SkAndroidCodec_DEFINED
 #define SkAndroidCodec_DEFINED
 
@@ skipping 35 matching lines @@
 
 
     const SkImageInfo& getInfo() const { return fInfo; }
 
     /**
      *  Format of the encoded data.
      */
     SkEncodedFormat getEncodedFormat() const { return this->onGetEncodedFormat(); }
 
     /**
+     *  @param requestedColorType Color type requested by the client
+     *
+     *  If it is possible to decode to requestedColorType, this returns
+     *  requestedColorType.  Otherwise, this returns whichever color type
+     *  is suggested by the codec as the best match for the encoded data.
+     */
+    SkColorType computeOutputColorType(SkColorType requestedColorType);
+
+    /**
+     *  @param requestedUnpremul  Indicates if the client requested
+     *                            unpremultiplied output
+     *
+     *  Returns the appropriate alpha type to decode to.  If the image
+     *  has alpha, the value of requestedUnpremul will be honored.
+     */
+    SkAlphaType computeOutputAlphaType(bool requestedUnpremul);
+
+    /**
      *  Returns the dimensions of the scaled output image, for an input
      *  sampleSize.
      *
      *  When the sample size divides evenly into the original dimensions, the
      *  scaled output dimensions will simply be equal to the original
      *  dimensions divided by the sample size.
      *
      *  When the sample size does not divide even into the original
      *  dimensions, the codec may round up or down, depending on what is most
      *  efficient to decode.
@@ skipping 155 matching lines @@
     virtual SkCodec::Result onGetAndroidPixels(const SkImageInfo& info, void* pixels,
             size_t rowBytes, const AndroidOptions& options) = 0;
 
 private:
 
     // This will always be a reference to the info that is contained by the
     // embedded SkCodec.
     const SkImageInfo& fInfo;
 };
 #endif // SkAndroidCodec_DEFINED