Moved JsonPrefStore to use SequencedWorkerPool

chrome/browser/prefs/pref_service_unittest.cc

Index: chrome/browser/prefs/pref_service_unittest.cc
diff --git a/chrome/browser/prefs/pref_service_unittest.cc b/chrome/browser/prefs/pref_service_unittest.cc
index 782740bcbbf1b9da2ca7818c6add4c6dfe695486..7f128cfdf1d1d78d0be0d1a4b5c23f3361e706ee 100644
--- a/chrome/browser/prefs/pref_service_unittest.cc
+++ b/chrome/browser/prefs/pref_service_unittest.cc
@@ -9,6 +9,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/scoped_temp_dir.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/api/prefs/pref_change_registrar.h"
@@ -285,6 +286,8 @@ class PrefServiceUserFilePrefsTest : public testing::Test {
     ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &data_dir_));
     data_dir_ = data_dir_.AppendASCII("pref_service");
     ASSERT_TRUE(file_util::PathExists(data_dir_));
+
+    blocking_pool_ = new base::SequencedWorkerPool(1, "TestBlocking");
   }
 
   void ClearListValue(PrefService* prefs, const char* key) {
@@ -301,8 +304,10 @@ class PrefServiceUserFilePrefsTest : public testing::Test {
   ScopedTempDir temp_dir_;
   // The path to the directory where the test data is stored.
   FilePath data_dir_;
-  // A message loop that we can use as the file thread message loop.
+  // A message loop that we need for firing timers.
   MessageLoop message_loop_;
+  // A message loop that we can use as the file thread message loop.
+  scoped_refptr<base::SequencedWorkerPool> blocking_pool_;
 };
 
 // Verifies that ListValue and DictionaryValue pref with non emtpy default
@@ -315,7 +320,7 @@ TEST_F(PrefServiceUserFilePrefsTest, PreserveEmptyValue) {
       pref_file));
 
   PrefServiceMockBuilder builder;
-  builder.WithUserFilePrefs(pref_file, base::MessageLoopProxy::current());
+  builder.WithUserFilePrefs(pref_file, blocking_pool_.get());
   scoped_ptr<PrefService> prefs(builder.Create());
 
   // Register testing prefs.
@@ -344,7 +349,7 @@ TEST_F(PrefServiceUserFilePrefsTest, PreserveEmptyValue) {
 
   // Write to file.
   prefs->CommitPendingWrite();
-  MessageLoop::current()->RunAllPending();
+  blocking_pool_->Shutdown();
 
   // Compare to expected output.
   FilePath golden_output_file =