Weakly bind JsonPrefStore's async read task to avoid it coming back after shutdown has been initiat…

base/prefs/json_pref_store.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 "base/prefs/json_pref_store.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 262 matching lines @@
 
   initialized_ = false;
   error_delegate_.reset(error_delegate);
   if (path_.empty()) {
     scoped_ptr<ReadResult> no_file_result;
     no_file_result->error = PREF_READ_ERROR_FILE_NOT_SPECIFIED;
     OnFileRead(no_file_result.Pass());
     return;
   }
 
+  // Weakly binds the read task so that it doesn't kick in during shutdown.
   base::PostTaskAndReplyWithResult(
       sequenced_task_runner_,
       FROM_HERE,
       base::Bind(&ReadPrefsFromDisk, path_, alternate_path_),
-      base::Bind(&JsonPrefStore::OnFileRead, this));
+      base::Bind(&JsonPrefStore::OnFileRead, AsWeakPtr()));
 }
 
 void JsonPrefStore::CommitPendingWrite() {
   DCHECK(CalledOnValidThread());
 
   if (writer_.HasPendingWrite() && !read_only_)
     writer_.DoScheduledWrite();
 }
 
 void JsonPrefStore::ReportValueChanged(const std::string& key) {
@@ skipping 61 matching lines @@
       case PREF_READ_ERROR_MAX_ENUM:
         NOTREACHED();
         break;
     }
   }
 
   if (pref_filter_) {
     filtering_in_progress_ = true;
     const PrefFilter::PostFilterOnLoadCallback post_filter_on_load_callback(
         base::Bind(
-            &JsonPrefStore::FinalizeFileRead, this, initialization_successful));
+            &JsonPrefStore::FinalizeFileRead, AsWeakPtr(),
+            initialization_successful));
     pref_filter_->FilterOnLoad(post_filter_on_load_callback,
                                unfiltered_prefs.Pass());
   } else {
     FinalizeFileRead(initialization_successful, unfiltered_prefs.Pass(), false);
   }
 }
 
 JsonPrefStore::~JsonPrefStore() {
   CommitPendingWrite();
 }
@@ skipping 52 matching lines @@
 
   if (error_delegate_ && read_error_ != PREF_READ_ERROR_NONE)
     error_delegate_->OnError(read_error_);
 
   FOR_EACH_OBSERVER(PrefStore::Observer,
                     observers_,
                     OnInitializationCompleted(true));
 
   return;
 }