Add support for multi resolution icons

ui/gfx/image.h

Index: ui/gfx/image.h
diff --git a/ui/gfx/image.h b/ui/gfx/image.h
index fddf4da27eb98ca4f11a95dd90b59a8125c9ff9f..0897bae434f69f51f195c67d980ecbb24d110af1 100644
--- a/ui/gfx/image.h
+++ b/ui/gfx/image.h
@@ -15,6 +15,7 @@
 #pragma once
 
 #include <map>
+#include <vector>
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
@@ -44,11 +45,18 @@ class Image {
   // Creates a new image with the default representation. The object will take
   // ownership of the image.
   explicit Image(const SkBitmap* bitmap);
+  // To create an Image that supports multiple resolutions pass a vector
+  // of bitmaps, one for each resolution.
+  explicit Image(const std::vector<const SkBitmap*>& bitmaps);
+
 #if defined(OS_LINUX)
   // Does not increase |pixbuf|'s reference count; expects to take ownership.
+  // TODO  Add support for multiple resolutions when necessary.

[Robert Sesek, 2011/04/18 22:48:13]

TODO(sail): ...

[Nico, 2011/04/18 22:51:35]

I'd just remove this TODO. Speculative TODOs don't help.

[sail, 2011/04/19 00:21:53]

Done. Removed.

   explicit Image(GdkPixbuf* pixbuf);
 #elif defined(OS_MACOSX)
   // Does not retain |image|; expects to take ownership.
+  // A single NSImage object can contain multiple bitmaps so there's no reason
+  // to pass a vector of these.
   explicit Image(NSImage* image);
 #endif
 
@@ -64,6 +72,9 @@ class Image {
   operator NSImage*();
 #endif
 
+  size_t GetNumberOfSkBitmaps();

[Robert Sesek, 2011/04/18 22:48:13]

Please add some comments and unit tests for these methods.

Additionally, I'd like to see tests for converting a multi-resolution
SkBitmap-backed gfx::Image to an NSImage, and vice versa. These behaviors should
be well-defined (and documented if they don't do what's expected).

+  const SkBitmap* GetSkBitmapAtIndex(size_t index);
+
   // Inspects the representations map to see if the given type exists.
   bool HasRepresentation(RepresentationType type);