Load 2x resources on demand

ui/gfx/image/image_skia_util_mac.mm

 // 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.
 
 #include "ui/gfx/image/image_skia_util_mac.h"
 
 #include <cmath>
 #include <limits>
 
 #import <AppKit/AppKit.h>
@@ skipping 72 matching lines @@
   NSImage* image = [NSImage imageNamed:@"NSApplicationIcon"];
   return ImageSkiaFromResizedNSImage(image,
                                      NSMakeSize(desired_size, desired_size));
 }
 
 NSImage* NSImageFromImageSkia(const gfx::ImageSkia& image_skia) {
   if (image_skia.isNull())
     return nil;
 
   scoped_nsobject<NSImage> image([[NSImage alloc] init]);
-
-  std::vector<gfx::ImageSkiaRep> image_reps = image_skia.GetRepresentations();
+  image_skia.EnsureRepsForSupportedScaleFactors();
+  std::vector<gfx::ImageSkiaRep> image_reps = image_skia.image_reps();
   for (std::vector<gfx::ImageSkiaRep>::const_iterator it = image_reps.begin();
        it != image_reps.end(); ++it) {
     [image addRepresentation:
         gfx::SkBitmapToNSBitmapImageRep(it->sk_bitmap())];
   }
 
   [image setSize:NSMakeSize(image_skia.width(), image_skia.height())];
   return [image.release() autorelease];
 }
 
 NSImage* NSImageFromImageSkiaWithColorSpace(const gfx::ImageSkia& image_skia,
                                             CGColorSpaceRef color_space) {
   if (image_skia.isNull())
     return nil;
 
   scoped_nsobject<NSImage> image([[NSImage alloc] init]);
-
-  const std::vector<gfx::ImageSkiaRep>& image_reps =
-      image_skia.GetRepresentations();
+  image_skia.EnsureRepsForSupportedScaleFactors();
+  std::vector<gfx::ImageSkiaRep> image_reps = image_skia.image_reps();
   for (std::vector<gfx::ImageSkiaRep>::const_iterator it = image_reps.begin();
        it != image_reps.end(); ++it) {
     [image addRepresentation:
         gfx::SkBitmapToNSBitmapImageRepWithColorSpace(it->sk_bitmap(),
                                                       color_space)];
   }
 
   [image setSize:NSMakeSize(image_skia.width(), image_skia.height())];
   return [image.release() autorelease];
 }
 
 }  // namespace gfx