Add a helper to resource bundle to get an NSImage back....

app/resource_bundle_mac.mm

Index: app/resource_bundle_mac.mm
===================================================================
--- app/resource_bundle_mac.mm	(revision 24269)
+++ app/resource_bundle_mac.mm	(working copy)
@@ -17,6 +17,7 @@
 #include "base/path_service.h"
 #include "base/string_piece.h"
 #include "base/string_util.h"
+#include "skia/ext/skia_utils_mac.h"
 
 ResourceBundle::~ResourceBundle() {
   FreeImages();
@@ -116,3 +117,14 @@
                data.length() / 2);
   return msg;
 }
+
+NSImage* ResourceBundle::GetNSImageNamed(int resource_id) {
+  // Currently this doesn't make a cache holding these as NSImages because
+  // GetBitmapNamed has a cache, and we don't want to double cache.
+  SkBitmap* bitmap = GetBitmapNamed(resource_id);
+  if (!bitmap)
+    return nil;
+
+  NSImage* nsimage = gfx::SkBitmapToNSImage(*bitmap);
+  return nsimage;
+}