Crop images from custom themes before storing them into the theme pack

chrome/browser/themes/theme_service_mac.mm

 // Copyright (c) 2011 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 "chrome/browser/themes/theme_service.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/logging.h"
 #include "chrome/browser/themes/browser_theme_pack.h"
@@ skipping 34 matching lines @@
   NSImageMap::const_iterator nsimage_iter = nsimage_cache_.find(id);
   if (nsimage_iter != nsimage_cache_.end())
     return nsimage_iter->second;
 
   // Why don't we load the file directly into the image instead of the whole
   // gfx::Image > native conversion?
   // - For consistency with other platforms.
   // - To get the generated tinted images.
   NSImage* nsimage = nil;
   if (theme_pack_.get()) {
-    const gfx::Image* image = theme_pack_->GetImageNamed(id);
-    if (image)
-      nsimage = image->ToNSImage();
+    gfx::Image image = theme_pack_->GetImageNamed(id);
+    if (!image.IsEmpty())
+      nsimage = image.ToNSImage();
   }
 
   // If the theme didn't override this image then load it from the resource
   // bundle.
   if (!nsimage) {
     nsimage = rb_.GetNativeImageNamed(id).ToNSImage();
   }
 
   // We loaded successfully.  Cache the image.
   if (nsimage) {
@@ skipping 248 matching lines @@
   }
   nscolor_cache_.clear();
 
   // Free gradients.
   for (NSGradientMap::iterator i = nsgradient_cache_.begin();
        i != nsgradient_cache_.end(); i++) {
     [i->second release];
   }
   nsgradient_cache_.clear();
 }