Fix login visual hitch on chromebook

chrome/browser/chromeos/login/user_image_loader.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_USER_IMAGE_LOADER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USER_IMAGE_LOADER_H_
 
 #include <map>
 #include <string>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/image_decoder.h"
 
 class MessageLoop;
 class SkBitmap;
 
 namespace chromeos {
 
 class UserImage;
 
 // A facility to read a file containing user image asynchronously in the IO
 // thread. Returns the image in the form of an SkBitmap.
 class UserImageLoader : public base::RefCountedThreadSafe<UserImageLoader>,
                         public ImageDecoder::Delegate {
  public:
   // Callback used to indicate that image has been loaded.
   typedef base::Callback<void(const UserImage& user_image)> LoadedCallback;
 
   explicit UserImageLoader(ImageDecoder::ImageCodec image_codec);
 
   // Start reading the image from |filepath| on the file thread. Calls
   // |loaded_cb| when image has been successfully loaded.
   // If |size| is positive, image is cropped and (if needed) downsized to
   // |size|x|size| pixels.
   void Start(const std::string& filepath, int size,
              const LoadedCallback& loaded_cb);
 
  private:
   friend class base::RefCountedThreadSafe<UserImageLoader>;
 
+  // Token name for user image loader.
+  static const char* kUserImageLoaderTokenName;

[Nikita (slow), 2013/01/18 16:40:13]

static const char kUserImageLoaderTokenName[]

[Joao da Silva, 2013/01/18 17:24:58]

This could also be hidden in the .cc file, in an anonymous namespace.

+
   // Contains attributes we need to know about each image we decode.
   struct ImageInfo {
     ImageInfo(int size, const LoadedCallback& loaded_cb);
     ~ImageInfo();
 
     const int size;
     const LoadedCallback loaded_cb;
   };
 
   typedef std::map<const ImageDecoder*, ImageInfo> ImageInfoMap;
@@ skipping 12 matching lines @@
   // The message loop object of the thread in which we notify the delegate.
   MessageLoop* target_message_loop_;
 
   // Specify how the file should be decoded in the utility process.
   const ImageDecoder::ImageCodec image_codec_;
 
   // Holds info structures about all images we're trying to decode.
   // Accessed only on FILE thread.
   ImageInfoMap image_info_map_;
 
+  base::SequencedWorkerPool::SequenceToken sequence_token_;
+
   DISALLOW_COPY_AND_ASSIGN(UserImageLoader);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USER_IMAGE_LOADER_H_