add ImageGenerator::NewFromData to porting layer

include/core/SkImage.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImage_DEFINED
 #define SkImage_DEFINED
 
@@ skipping 45 matching lines @@
 
     virtual bool isOpaque() const { return false; }
 
     /**
      *  Construct a new SkImage based on the given ImageGenerator.
      *  This function will always take ownership of the passed
      *  ImageGenerator.  Returns NULL on error.
      */
     static SkImage* NewFromGenerator(SkImageGenerator*);
 
+    /**
+     *  Construct a new SkImage based on the specified encoded data. Returns NULL on failure,
+     *  which can mean that the format of the encoded data was not recognized/supported.
+     *
+     *  Regardless of success or failure, the caller is responsible for managing their ownership
+     *  of the data.
+     */
+    static SkImage* NewFromData(SkData* data);
+
     int width() const { return fWidth; }
     int height() const { return fHeight; }
     uint32_t uniqueID() const { return fUniqueID; }
 
     /**
      * Return the GrTexture that stores the image pixels. Calling getTexture
      * does not affect the reference count of the GrTexture object.
      * Will return NULL if the image does not use a texture.
      */
     GrTexture* getTexture();
@@ skipping 82 matching lines @@
      *  Draw the image, cropped to the src rect, to the dst rect of a canvas.
      *  If src is larger than the bounds of the image, the rest of the image is
      *  filled with transparent black pixels.
      *
      *  See SkCanvas::drawBitmapRectToRect for similar behavior.
      */
     void drawRect(SkCanvas*, const SkRect* src, const SkRect& dst, const SkPaint*) const;
 };
 
 #endif