Add support for multi resolution icons

chrome/browser/themes/theme_service_mac.mm

Index: chrome/browser/themes/theme_service_mac.mm
diff --git a/chrome/browser/themes/theme_service_mac.mm b/chrome/browser/themes/theme_service_mac.mm
index 30d359ee203040d8f36aca70ad7887d964e97253..cf9ad9926e7860da85d69054db1ee6e27199694e 100644
--- a/chrome/browser/themes/theme_service_mac.mm
+++ b/chrome/browser/themes/theme_service_mac.mm
@@ -44,13 +44,15 @@ NSImage* ThemeService::GetNSImageNamed(int id, bool allow_default) const {
   // SkBitmap > native conversion?
   // - For consistency with other platforms.
   // - To get the generated tinted images.
-  SkBitmap* bitmap = GetBitmapNamed(id);
-  NSImage* nsimage = gfx::SkBitmapToNSImage(*bitmap);
-
-  // We loaded successfully.  Cache the image.
-  if (nsimage) {
-    nsimage_cache_[id] = [nsimage retain];
-    return nsimage;
+  std::vector<SkBitmap*> bitmaps;
+  if (GetBitmapsNamed(id, bitmaps)) {
+    NSImage* nsimage = gfx::SkBitmapsToNSImage(bitmaps);
+
+    // We loaded successfully.  Cache the image.
+    if (nsimage) {
+      nsimage_cache_[id] = [nsimage retain];
+      return nsimage;
+    }
   }
 
   // We failed to retrieve the bitmap, show a debugging red square.