Moved JsonPrefStore to use SequencedWorkerPool

chrome/browser/prefs/pref_service_mock_builder.cc

Index: chrome/browser/prefs/pref_service_mock_builder.cc
diff --git a/chrome/browser/prefs/pref_service_mock_builder.cc b/chrome/browser/prefs/pref_service_mock_builder.cc
index 27828828c2e1b1a3ebcdbd22d0dcbd142dadef21..77d8080c1b15b28ec3ec29432703d1998fd52f75 100644
--- a/chrome/browser/prefs/pref_service_mock_builder.cc
+++ b/chrome/browser/prefs/pref_service_mock_builder.cc
@@ -77,16 +77,17 @@ PrefServiceMockBuilder::WithCommandLine(CommandLine* command_line) {
 
 PrefServiceMockBuilder&
 PrefServiceMockBuilder::WithUserFilePrefs(const FilePath& prefs_file) {
-  return WithUserFilePrefs(prefs_file,
-                           BrowserThread::GetMessageLoopProxyForThread(
-                               BrowserThread::FILE));
+  return WithUserFilePrefs(
+      prefs_file,
+      JsonPrefStore::GetTaskRunnerForFile(prefs_file,
+                                          BrowserThread::GetBlockingPool()));
 }
 
 PrefServiceMockBuilder&
 PrefServiceMockBuilder::WithUserFilePrefs(
     const FilePath& prefs_file,
-    base::MessageLoopProxy* message_loop_proxy) {
-  user_prefs_ = new JsonPrefStore(prefs_file, message_loop_proxy);
+    base::SequencedTaskRunner* task_runner) {
+  user_prefs_ = new JsonPrefStore(prefs_file, task_runner);
   return *this;
 }