Makes ImageSkia more like SkBitmap

ui/gfx/image/image_mac.mm

 // Copyright (c) 2011 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.
 
 #import <AppKit/AppKit.h>
+#import <vector>
 
+#include "base/memory/scoped_nsobject.h"
 #include "base/memory/scoped_ptr.h"
 #include "skia/ext/skia_utils_mac.h"
 #include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/image/image_skia.h"
 
 namespace gfx {
 namespace internal {
 
-bool NSImageToSkBitmaps(NSImage* image, std::vector<const SkBitmap*>* bitmaps) {
+gfx::ImageSkia NSImageToImageSkia(NSImage* image) {
+  gfx::ImageSkia image_skia;
   for (NSImageRep* imageRep in [image representations]) {
-    scoped_ptr<SkBitmap> bitmap(new SkBitmap(
-        gfx::NSImageRepToSkBitmap(imageRep, [imageRep size], false)));
-    if (bitmap->isNull())
-      return false;
-    bitmaps->push_back(bitmap.release());
+    NSSize imageRepSize = [imageRep size];
+    SkBitmap bitmap(gfx::NSImageRepToSkBitmap(imageRep, imageRepSize, false));
+    if (!bitmap.isNull() && !bitmap.empty()) {
+      float scaleFactor = imageRepSize.width / [image size].width;
+      image_skia.AddBitmapForScale(bitmap, scaleFactor);
+    }
   }
-  return true;
+  return image_skia;
+}
+
+NSImage* ImageSkiaToNSImage(const gfx::ImageSkia* image_skia) {
+  if (image_skia->empty())
+    return nil;
+
+  scoped_nsobject<NSImage> image([[NSImage alloc] init]);
+
+  const std::vector<SkBitmap> bitmaps = image_skia->bitmaps();
+  for (std::vector<SkBitmap>::const_iterator it = bitmaps.begin();
+       it != bitmaps.end(); ++it) {
+    [image addRepresentation:gfx::SkBitmapToNSBitmapImageRep(*it)];
+  }
+
+  [image setSize:NSMakeSize(image_skia->width(), image_skia->height())];
+  return [image.release() autorelease];
 }
 
 }  // namespace internal
 }  // namespace gfx