Adds an iOS implementation of gfx::Image.

ui/gfx/image/image_util.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_IMAGE_IMAGE_UTIL_H_
 #define UI_GFX_IMAGE_IMAGE_UTIL_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "ui/base/ui_export.h"
 
 namespace gfx {
 class Image;
 }
 
 namespace gfx {
 
 // Creates an image from the given PNG-encoded input.  The caller owns the
 // returned Image.  If there was an error creating the image, returns NULL.
 UI_EXPORT Image* ImageFromPNGEncodedData(const unsigned char* input,
                                          size_t input_size);
 
+// Fills the |dst| vector with PNG-encoded bytes based on the given Image.
+// Returns true if the Image was encoded successfully.
+UI_EXPORT bool PNGEncodedDataFromImage(const Image& image,
+                                       std::vector<unsigned char>* dst);
+
 // Creates an image from the given JPEG-encoded input.  The caller owns the
 // returned Image.  If there was an error creating the image, returns an
 // IsEmpty() Image.
 UI_EXPORT Image ImageFromJPEGEncodedData(const unsigned char* input,
                                          size_t input_size);
 
-// Fills the |dst| vector with PNG-encoded bytes based on the given Image.
-// Returns true if the Image was encoded successfully.
-UI_EXPORT bool PNGEncodedDataFromImage(const Image& image,
-                                       std::vector<unsigned char>* dst);
-
 // Fills the |dst| vector with JPEG-encoded bytes based on the given Image.
 // |quality| determines the compression level, 0 == lowest, 100 == highest.
 // Returns true if the Image was encoded successfully.
 UI_EXPORT bool JPEGEncodedDataFromImage(const Image& image,
                                         int quality,
                                         std::vector<unsigned char>* dst);
 
 }
 
 #endif  // UI_GFX_IMAGE_IMAGE_UTIL_H_