indexeddb: Removed use of dangling ptr in writeBlobToFileOnIOThread.

content/public/browser/indexed_db_context.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 CONTENT_PUBLIC_BROWSER_INDEXED_DB_CONTEXT_H_
 #define CONTENT_PUBLIC_BROWSER_INDEXED_DB_CONTEXT_H_
 
+#include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/indexed_db_info.h"
 
 namespace base {
 class SequencedTaskRunner;
-class TaskRunner;
 }
 
 namespace content {
 
 // Represents the per-BrowserContext IndexedDB data.
 // Call these methods only via the exposed TaskRunner.
 class IndexedDBContext : public base::RefCountedThreadSafe<IndexedDBContext> {
  public:
   // Only call the below methods by posting to this TaskRunner.
-  virtual base::TaskRunner* TaskRunner() const = 0;
+  virtual base::SequencedTaskRunner* TaskRunner() const = 0;
 
   // Methods used in response to QuotaManager requests.
   virtual std::vector<IndexedDBInfo> GetAllOriginsInfo() = 0;
   virtual int64 GetOriginDiskUsage(const GURL& origin_url) = 0;
 
   // Deletes all indexed db files for the given origin.
   virtual void DeleteForOrigin(const GURL& origin_url) = 0;
 
   // Get the file name of the local storage file for the given origin.
   virtual base::FilePath GetFilePathForTesting(
       const std::string& origin_id) const = 0;
   // Set the task runner for tests if browser main loop is not initialized.
   virtual void SetTaskRunnerForTesting(
       base::SequencedTaskRunner* task_runner) = 0;
 
  protected:
   friend class base::RefCountedThreadSafe<IndexedDBContext>;
   virtual ~IndexedDBContext() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_INDEXED_DB_CONTEXT_H_