linux_aura: run IconLoader::ReadIcon on the UI thread.

chrome/browser/icon_loader_chromeos.cc

 // 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 "chrome/browser/icon_loader.h"
 
 #include <map>
 #include <string>
 #include <utility>
 
@@ skipping 168 matching lines @@
 }
 
 }  // namespace
 
 // static
 IconGroupID IconLoader::ReadGroupIDFromFilepath(
     const base::FilePath& filepath) {
   return StringToLowerASCII(filepath.Extension());
 }
 
+// static
 bool IconLoader::IsIconMutableFromFilepath(const base::FilePath&) {
   return false;
 }
 
+// static
+content::BrowserThread::ID IconLoader::ReadIconThreadID() {
+  return content::BrowserThread::FILE;
+}
+
 void IconLoader::ReadIcon() {
   static base::LazyInstance<IconMapper>::Leaky icon_mapper =
       LAZY_INSTANCE_INITIALIZER;
   int idr = icon_mapper.Get().Lookup(group_, icon_size_);
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   gfx::ImageSkia image_skia(ResizeImage(*(rb.GetImageNamed(idr)).ToImageSkia(),
                                         IconSizeToDIPSize(icon_size_)));
   image_skia.MakeThreadSafe();
   image_.reset(new gfx::Image(image_skia));
   target_message_loop_->PostTask(
       FROM_HERE, base::Bind(&IconLoader::NotifyDelegate, this));
 }