Moved JsonPrefStore to use SequencedWorkerPool

chrome/service/service_process_prefs.h

Index: chrome/service/service_process_prefs.h
diff --git a/chrome/service/service_process_prefs.h b/chrome/service/service_process_prefs.h
index ef6d836e98276b271ce8801ca7c9f9ca918fa567..3ba05e33259126ecd48cdc114b004ce08e2a4edb 100644
--- a/chrome/service/service_process_prefs.h
+++ b/chrome/service/service_process_prefs.h
@@ -12,16 +12,16 @@
 namespace base {
 class DictionaryValue;
 class ListValue;
+class SequencedTaskRunner;
 }
 
 // Manages persistent preferences for the service process. This is basically a
 // thin wrapper around JsonPrefStore for more comfortable use.
 class ServiceProcessPrefs {
  public:
-  // |file_message_loop_proxy| is the MessageLoopProxy for a thread on which
-  // file I/O can be done.
+  // |sequenced_task_runner| must be a shutdown-blocking task runner.
   ServiceProcessPrefs(const FilePath& pref_filename,
-                      base::MessageLoopProxy* file_message_loop_proxy);
+                      base::SequencedTaskRunner* task_runner);
   ~ServiceProcessPrefs();
 
   // Read preferences from the backing file.