Make image_decoder a Leaky LazyInstance

chrome/browser/chromeos/login/users/avatar/user_image_loader.h

Index: chrome/browser/chromeos/login/users/avatar/user_image_loader.h
diff --git a/chrome/browser/chromeos/login/users/avatar/user_image_loader.h b/chrome/browser/chromeos/login/users/avatar/user_image_loader.h
index 10c7be458e2e89630835d0ca95f05666b40e3a52..70340cf92b1bf43dcf1cce1fb8ceb7c6fd09240d 100644
--- a/chrome/browser/chromeos/login/users/avatar/user_image_loader.h
+++ b/chrome/browser/chromeos/login/users/avatar/user_image_loader.h
@@ -5,7 +5,7 @@
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_USERS_AVATAR_USER_IMAGE_LOADER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USERS_AVATAR_USER_IMAGE_LOADER_H_
 
-#include <map>
+#include <queue>
 #include <string>
 
 #include "base/callback.h"
@@ -67,7 +67,8 @@ class UserImageLoader : public base::RefCountedThreadSafe<UserImageLoader>,
     const LoadedCallback loaded_cb;
   };
 
-  typedef std::map<const ImageDecoder*, ImageInfo> ImageInfoMap;
+  typedef std::queue<ImageInfo> ImageInfoQueue;
+  typedef std::queue<std::vector<unsigned char>> ImageDataQueue;
 
   ~UserImageLoader() override;
 
@@ -82,9 +83,8 @@ class UserImageLoader : public base::RefCountedThreadSafe<UserImageLoader>,
 
   // ImageDecoder::Delegate implementation. These callbacks will only be invoked
   // via the |background_task_runner_|.
-  void OnImageDecoded(const ImageDecoder* decoder,
-                      const SkBitmap& decoded_image) override;
-  void OnDecodeImageFailed(const ImageDecoder* decoder) override;
+  void OnImageDecoded(const SkBitmap& decoded_image) override;
+  void OnDecodeImageFailed() override;
 
   // The foreground task runner on which |this| is instantiated, Start() is
   // called and LoadedCallbacks are invoked.
@@ -99,7 +99,8 @@ class UserImageLoader : public base::RefCountedThreadSafe<UserImageLoader>,
 
   // Holds information about the images currently being decoded. Accessed via
   // |background_task_runner_| only.
-  ImageInfoMap image_info_map_;
+  ImageInfoQueue image_info_queue_;
+  ImageDataQueue image_data_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(UserImageLoader);
 };