ProfileInfoCache: Don't delete ProfileAvatarDownloader while we're being called by it

chrome/browser/profiles/profile_info_cache.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_PROFILES_PROFILE_INFO_CACHE_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_INFO_CACHE_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 213 matching lines @@
   mutable std::map<std::string, gfx::Image*> cached_avatar_images_;
   // Marks a profile picture as loading from disk. This prevents a picture from
   // loading multiple times.
   mutable std::map<std::string, bool> cached_avatar_images_loading_;
 
   // Map of profile pictures currently being downloaded from the remote
   // location and the ProfileAvatarDownloader instances downloading them.
   // This prevents a picture from being downloaded multiple times. The
   // ProfileAvatarDownloader instances are deleted when the download completes
   // or when the ProfileInfoCache is destroyed.
-  mutable std::map<std::string, ProfileAvatarDownloader*>
+  std::map<std::string, ProfileAvatarDownloader*>
       avatar_images_downloads_in_progress_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileInfoCache);
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_INFO_CACHE_H_