Release password store on UI loop when worker is stopped so that password

service and thread can be shut down in proper order.

BUG=274705

Review URL: https://chromiumcodereview.appspot.com/23463033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@223427 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync/glue/password_model_worker.cc

@@ -22,6 +22,7 @@ PasswordModelWorker::PasswordModelWorker(
 }
 
 void PasswordModelWorker::RegisterForLoopDestruction() {
+  base::AutoLock lock(password_store_lock_);
   password_store_->ScheduleTask(
       base::Bind(&PasswordModelWorker::RegisterForPasswordLoopDestruction,
                  this));
@@ -30,13 +31,22 @@ void PasswordModelWorker::RegisterForLoopDestruction() {
 syncer::SyncerError PasswordModelWorker::DoWorkAndWaitUntilDoneImpl(
     const syncer::WorkCallback& work) {
   syncer::SyncerError error = syncer::UNSET;
-  if (password_store_->ScheduleTask(
-          base::Bind(&PasswordModelWorker::CallDoWorkAndSignalTask,
-                     this, work, work_done_or_stopped(), &error))) {
+
+  bool scheduled = false;
+  {
+    base::AutoLock lock(password_store_lock_);
+    if (!password_store_.get())
+      return syncer::CANNOT_DO_WORK;
+
+    scheduled = password_store_->ScheduleTask(
+        base::Bind(&PasswordModelWorker::CallDoWorkAndSignalTask,
+                   this, work, work_done_or_stopped(), &error));
+  }
+
+  if (scheduled)
     work_done_or_stopped()->Wait();
-  } else {
+  else
     error = syncer::CANNOT_DO_WORK;
-  }
   return error;
 }
 
@@ -59,4 +69,11 @@ void PasswordModelWorker::RegisterForPasswordLoopDestruction() {
   SetWorkingLoopToCurrent();
 }
 
+void PasswordModelWorker::RequestStop() {
+  ModelSafeWorker::RequestStop();
+
+  base::AutoLock lock(password_store_lock_);
+  password_store_ = NULL;
+}
+
 }  // namespace browser_sync

chrome/browser/sync/glue/password_model_worker.h

@@ -31,6 +31,7 @@ class PasswordModelWorker : public syncer::ModelSafeWorker {
   // syncer::ModelSafeWorker implementation. Called on syncapi SyncerThread.
   virtual void RegisterForLoopDestruction() OVERRIDE;
   virtual syncer::ModelSafeGroup GetModelSafeGroup() OVERRIDE;
+  virtual void RequestStop() OVERRIDE;
 
  protected:
   virtual syncer::SyncerError DoWorkAndWaitUntilDoneImpl(
@@ -48,6 +49,9 @@ class PasswordModelWorker : public syncer::ModelSafeWorker {
   // observer.
   void RegisterForPasswordLoopDestruction();
 
+  // |password_store_| is used on password thread but released on UI thread.
+  // Protected by |password_store_lock_|.
+  base::Lock password_store_lock_;
   scoped_refptr<PasswordStore> password_store_;
   DISALLOW_COPY_AND_ASSIGN(PasswordModelWorker);
 };

sync/internal_api/public/engine/model_safe_worker.h

@@ -83,8 +83,8 @@ class SYNC_EXPORT ModelSafeWorker
   SyncerError DoWorkAndWaitUntilDone(const WorkCallback& work);
 
   // Soft stop worker by setting stopped_ flag. Called when sync is disabled
-  // or browser is shutting down.
-  void RequestStop();
+  // or browser is shutting down. Called on UI loop.
+  virtual void RequestStop();
 
   virtual ModelSafeGroup GetModelSafeGroup() = 0;