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 24 matching lines @@
      *  If this data represents an encoded image that we know how to decode,
      *  return an SkAndroidCodec that can decode it. Otherwise return NULL.
      *
      *  The SkPngChunkReader handles unknown chunks in PNGs.
      *  See SkCodec.h for more details.
      *
      *  Will take a ref if it returns a codec, else will not affect the data.
      */
     static SkAndroidCodec* NewFromData(SkData*, SkPngChunkReader* = NULL);
 
+    /**
+     *  @param requestedColorType Color type requested by the client
+     *  @param suggestedColorType Color type suggested by SkAndroidCodec
+     *  @param suggestedAlphaType Alpha type suggested by SkAndroidCodec
+     *
+     *  @return If it is possible to decode to requestedColorType, this returns
+     *          requestedColorType.  Otherwise, this returns kN32_SkColorType.
+     */
+    static SkColorType FixRequestedColorType(SkColorType requestedColorType,
+            SkColorType suggestedColorType, SkAlphaType suggestedAlphaType);
+
+    /**
+     *  @param requestedUnpremul  Indicates if the client requested
+     *                            unpremultiplied output
+     *  @param suggestedAlphaType Alpha type suggested by SkAndroidCodec
+     *
+     *  @return Returns the appropriate alpha type to decode to.  If the image
+     *          has alpha, the value of requestedUnpremul will be honored.
+     */
+    static SkAlphaType FixRequestedAlphaType(bool requestedUnpremul,
+            SkAlphaType suggestedAlphaType);
+
     virtual ~SkAndroidCodec() {}
 
 
     const SkImageInfo& getInfo() const { return fInfo; }
 
     /**
      *  Format of the encoded data.
      */
     SkEncodedFormat getEncodedFormat() const { return this->onGetEncodedFormat(); }
 
@@ skipping 166 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