Add scale factor and 2x resources from webkit and plumb through to ContentClient.

webkit/support/platform_support_mac.mm

 // Copyright (c) 2012 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 "webkit/support/platform_support.h"
 
 #import <AppKit/AppKit.h>
 #include <AvailabilityMacros.h>
 #import <Foundation/Foundation.h>
 #import <objc/objc-runtime.h>
@@ skipping 199 matching lines @@
   // We assume the application is bundled.
   if (!base::mac::AmIBundled()) {
     LOG(FATAL) << "Failed to locate resources. The applicaiton is not bundled.";
   }
   PathService::Get(base::DIR_EXE, &path);
   path = path.Append(FilePath::kParentDirectory);
   return path.AppendASCII("Resources");
 }
 
 base::StringPiece TestWebKitPlatformSupport::GetDataResource(int resource_id) {
+  base::StringPiece res;
+  if (g_resource_data_pack)
+    g_resource_data_pack->GetStringPiece(resource_id, &res);
+  return res;
+}
+
+base::StringPiece TestWebKitPlatformSupport::GetImageResource(
+    int resource_id,
+    float scale_factor) {
   switch (resource_id) {
   case IDR_BROKENIMAGE: {
     // Use webkit's broken image icon (16x16)
     CR_DEFINE_STATIC_LOCAL(std::string, broken_image_data, ());
     if (broken_image_data.empty()) {
       FilePath path = GetResourcesFilePath();
       // In order to match WebKit's colors for the missing image, we have to
       // use a PNG. The GIF doesn't have the color range needed to correctly
       // match the TIFF they use in Safari.
       path = path.AppendASCII("missingImage.png");
@@ skipping 16 matching lines @@
       }
     }
     return resize_corner_data;
   }
   }
   base::StringPiece res;
   if (g_resource_data_pack)
     g_resource_data_pack->GetStringPiece(resource_id, &res);
   return res;
 }