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.
   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, 2011/04/15 20:27:20]

I'm not in love with this interface. It's not really intuitive as to what
happens with the extra versions during conversion between formats.

I think I'd prefer something along the lines of:
  gfx::Image* GetVersionBestMatchingSize(gfx::Size);

But that itself can make things tricky...

[sail, 2011/04/16 01:25:00]

I agree the name sucks. It'll be supper easy to change in the future though. My
goal is that no one outside chrome/browser/theme and ui/base/resource will have
to use this API.

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