Mac: Disable loading 2x bitmaps on 10.5 and 10.6

ui/base/resource/resource_bundle_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 "ui/base/resource/resource_bundle.h"
 
 #import <AppKit/AppKit.h>
 
 #include "base/basictypes.h"
 #include "base/file_path.h"
 #include "base/mac/mac_util.h"
 #include "base/memory/scoped_nsobject.h"
 #include "base/synchronization/lock.h"
+#include "base/sys_info.h"
 #include "base/sys_string_conversions.h"
 #include "ui/gfx/image.h"
 
 namespace ui {
 
 namespace {
 
 FilePath GetResourcesPakFilePath(NSString* name, NSString* mac_locale) {
   NSString *resource_path;
   // Some of the helper processes need to be able to fetch resources
@@ skipping 16 matching lines @@
 
 }  // namespace
 
 // static
 FilePath ResourceBundle::GetResourcesFilePath() {
   return GetResourcesPakFilePath(@"chrome", nil);
 }
 
 // static
 FilePath ResourceBundle::GetLargeIconResourcesFilePath() {
-  return GetResourcesPakFilePath(@"theme_resources_large", nil);
+  int32 major = 0;
+  int32 minor = 0;
+  int32 bugfix = 0;
+  base::SysInfo::OperatingSystemVersionNumbers(&major, &minor, &bugfix);
+
+  // Only load the large resource pak on if we're running on 10.7 or above.
+  if (major > 10 || (major == 10 && minor >= 7))
+    return GetResourcesPakFilePath(@"theme_resources_large", nil);
+  else
+    return FilePath();
 }
 
 // static
 FilePath ResourceBundle::GetLocaleFilePath(const std::string& app_locale) {
   NSString* mac_locale = base::SysUTF8ToNSString(app_locale);
 
   // Mac OS X uses "_" instead of "-", so swap to get a Mac-style value.
   mac_locale = [mac_locale stringByReplacingOccurrencesOfString:@"-"
                                                      withString:@"_"];
 
@@ skipping 59 matching lines @@
     images_[resource_id] = image;
     return *image;
   }
 
   LOG(WARNING) << "Unable to load image with id " << resource_id;
   NOTREACHED();  // Want to assert in debug mode.
   return *GetEmptyImage();
 }
 
 }  // namespace ui