Moved JsonPrefStore to use SequencedWorkerPool

chrome/browser/browser_process_impl.h

Index: chrome/browser/browser_process_impl.h
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index d5a1e5083b86f68cbfff9e2890ac43c38ee575b2..5f18e625ce7f87ffa56319f0f9c9a470dffc7bbb 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -31,6 +31,10 @@ class RemoteDebuggingServer;
 class PluginsResourceService;
 #endif
 
+namespace base {
+class SequencedTaskRunner;
+}
+
 namespace policy {
 class BrowserPolicyConnector;
 class PolicyService;
@@ -41,7 +45,9 @@ class BrowserProcessImpl : public BrowserProcess,
                            public base::NonThreadSafe,
                            public PrefObserver {
  public:
-  explicit BrowserProcessImpl(const CommandLine& command_line);
+  // |local_state_task_runner| must be a shutdown-blocking task runner.
+  BrowserProcessImpl(base::SequencedTaskRunner* local_state_task_runner,
+                     const CommandLine& command_line);
   virtual ~BrowserProcessImpl();
 
   // Called before the browser threads are created.
@@ -226,6 +232,9 @@ class BrowserProcessImpl : public BrowserProcess,
 
   scoped_refptr<DownloadRequestLimiter> download_request_limiter_;
 
+  // Sequenced task runner for local state related I/O tasks.
+  const scoped_refptr<base::SequencedTaskRunner> local_state_task_runner_;
+
   // Ensures that the observers of plugin/print disable/enable state
   // notifications are properly added and removed.
   PrefChangeRegistrar pref_change_registrar_;