Moved JsonPrefStore to use SequencedWorkerPool instead of FILE thread. The pool also ensures that the same file requests are written in order received and that they block on shutdown.

BUG=153367
TEST=existing unit/browser tests

Review URL: https://codereview.chromium.org/11027070

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@165062 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 23 insertions, 15 deletions

diff --git a/chrome/browser/prefs/pref_service.cc b/chrome/browser/prefs/pref_service.cc
index 8862f7f..eedef9b 100644
--- a/chrome/browser/prefs/pref_service.cc
+++ b/chrome/browser/prefs/pref_service.cc
@@ -123,6 +123,7 @@ PrefServiceBase* PrefServiceBase::FromBrowserContext(BrowserContext* context) {
 // static
 PrefService* PrefService::CreatePrefService(
     const FilePath& pref_filename,
+    base::SequencedTaskRunner* pref_io_task_runner,
     policy::PolicyService* policy_service,
     PrefStore* extension_prefs,
     bool async) {
@@ -156,8 +157,7 @@ PrefService* PrefService::CreatePrefService(
   CommandLinePrefStore* command_line =
       new CommandLinePrefStore(CommandLine::ForCurrentProcess());
   JsonPrefStore* user = new JsonPrefStore(
-      pref_filename,
-      BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
+      pref_filename, pref_io_task_runner);
   DefaultPrefStore* default_pref_store = new DefaultPrefStore();
 
   PrefNotifierImpl* pref_notifier = new PrefNotifierImpl();
diff --git a/chrome/browser/prefs/pref_service.h b/chrome/browser/prefs/pref_service.h
index 82b9167..c855ef1 100644
--- a/chrome/browser/prefs/pref_service.h
+++ b/chrome/browser/prefs/pref_service.h
@@ -31,6 +31,10 @@ class PrefServiceObserver;
 class PrefStore;
 class PrefValueStore;
 
+namespace base {
+  class SequencedTaskRunner;
+}
+
 namespace syncer {
 class SyncableService;
 }
@@ -108,10 +112,12 @@ class PrefService : public PrefServiceBase, public base::NonThreadSafe {
   // the created PrefService or NULL if creation has failed. Note, it is
   // guaranteed that in asynchronous version initialization happens after this
   // function returned.
-  static PrefService* CreatePrefService(const FilePath& pref_filename,
-                                        policy::PolicyService* policy_service,
-                                        PrefStore* extension_pref_store,
-                                        bool async);
+  static PrefService* CreatePrefService(
+      const FilePath& pref_filename,
+      base::SequencedTaskRunner* pref_io_task_runner,
+      policy::PolicyService* policy_service,
+      PrefStore* extension_pref_store,
+      bool async);
 
   // Creates an incognito copy of the pref service that shares most pref stores
   // but uses a fresh non-persistent overlay for the user pref store and an
diff --git a/chrome/browser/prefs/pref_service_mock_builder.cc b/chrome/browser/prefs/pref_service_mock_builder.cc
index 2782882..77d8080 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;
 }
 
diff --git a/chrome/browser/prefs/pref_service_mock_builder.h b/chrome/browser/prefs/pref_service_mock_builder.h
index b939ca6..708b622 100644
--- a/chrome/browser/prefs/pref_service_mock_builder.h
+++ b/chrome/browser/prefs/pref_service_mock_builder.h
@@ -15,7 +15,7 @@ class FilePath;
 class PrefService;
 
 namespace base {
-class MessageLoopProxy;
+class SequencedTaskRunner;
 }
 
 namespace policy {
@@ -48,10 +48,11 @@ class PrefServiceMockBuilder {
   PrefServiceMockBuilder& WithCommandLine(CommandLine* command_line);
 
   // Specifies to use an actual file-backed user pref store.
+  // TODO(zelidrag): Remove the first overloaded method below.
   PrefServiceMockBuilder& WithUserFilePrefs(const FilePath& prefs_file);
   PrefServiceMockBuilder& WithUserFilePrefs(
       const FilePath& prefs_file,
-      base::MessageLoopProxy* message_loop_proxy);
+      base::SequencedTaskRunner* task_runner);
 
   // Creates the PrefService, invalidating the entire builder configuration.
   PrefService* Create();
diff --git a/chrome/browser/prefs/pref_service_unittest.cc b/chrome/browser/prefs/pref_service_unittest.cc
index 2dc90a8..cd046e8 100644
--- a/chrome/browser/prefs/pref_service_unittest.cc
+++ b/chrome/browser/prefs/pref_service_unittest.cc
@@ -315,7 +315,7 @@ TEST_F(PrefServiceUserFilePrefsTest, PreserveEmptyValue) {
       pref_file));
 
   PrefServiceMockBuilder builder;
-  builder.WithUserFilePrefs(pref_file, base::MessageLoopProxy::current());
+  builder.WithUserFilePrefs(pref_file, message_loop_.message_loop_proxy());
   scoped_ptr<PrefService> prefs(builder.Create());
 
   // Register testing prefs.
@@ -344,7 +344,7 @@ TEST_F(PrefServiceUserFilePrefsTest, PreserveEmptyValue) {
 
   // Write to file.
   prefs->CommitPendingWrite();
-  MessageLoop::current()->RunAllPending();
+  message_loop_.RunAllPending();
 
   // Compare to expected output.
   FilePath golden_output_file =