Add getYUV8Planes() API to SkCodec

src/codec/SkCodecImageGenerator.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.
  */
 
 #include "SkCodec.h"
 #include "SkData.h"
 #include "SkImageGenerator.h"
@@ skipping 21 matching lines @@
 private:
     /*
      * Takes ownership of codec
      * Refs the data
      */
     SkCodecImageGenerator(SkCodec* codec, SkData* data);
 
     SkAutoTDelete<SkCodec> fCodec;
     SkAutoTUnref<SkData> fData;
 
+    // FIXME: These fields are necessary only until we change the API of SkImageGenerator
+    //        to match SkCodec.  Once the API is changed, they should be removed.
+    int fYWidth;
+    int fUWidth;
+    int fVWidth;
+
     typedef SkImageGenerator INHERITED;
 };