[Sync] Make BackendMigrator not wait for full sync cycles

chrome/browser/sync/engine/sync_scheduler.cc

Index: chrome/browser/sync/engine/sync_scheduler.cc
diff --git a/chrome/browser/sync/engine/sync_scheduler.cc b/chrome/browser/sync/engine/sync_scheduler.cc
index 993b72755abcd019a89a4ff8380c7a91d5c9dbac..ea3a8474320c618c808efe663f6bb5f8f5e7ad6a 100644
--- a/chrome/browser/sync/engine/sync_scheduler.cc
+++ b/chrome/browser/sync/engine/sync_scheduler.cc
@@ -58,14 +58,18 @@ SyncScheduler::SyncSessionJob::SyncSessionJob()
 
 SyncScheduler::SyncSessionJob::~SyncSessionJob() {}
 
-SyncScheduler::SyncSessionJob::SyncSessionJob(SyncSessionJobPurpose purpose,
+SyncScheduler::SyncSessionJob::SyncSessionJob(
+    SyncSessionJobPurpose purpose,
     base::TimeTicks start,
     linked_ptr<sessions::SyncSession> session, bool is_canary_job,
-    const tracked_objects::Location& from_here) : purpose(purpose),
-        scheduled_start(start),
-        session(session),
-        is_canary_job(is_canary_job),
-        from_here(from_here) {
+    const base::Closure& on_success,
+    const tracked_objects::Location& from_here)
+  : purpose(purpose),
+    scheduled_start(start),
+    session(session),
+    is_canary_job(is_canary_job),
+    on_success(on_success),
+    from_here(from_here) {
 }
 
 const char* SyncScheduler::SyncSessionJob::GetPurposeString(
@@ -199,7 +203,7 @@ void SyncScheduler::CheckServerConnectionManagerStatus(
   }
 }
 
-void SyncScheduler::Start(Mode mode, ModeChangeCallback* callback) {
+void SyncScheduler::Start(Mode mode, const base::Closure& callback) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   std::string thread_name = MessageLoop::current()->thread_name();
   if (thread_name.empty())
@@ -213,8 +217,6 @@ void SyncScheduler::Start(Mode mode, ModeChangeCallback* callback) {
                  &SyncScheduler::SendInitialSnapshot));
   }
   started_ = true;
-  // TODO(sync): This will leak if StartImpl is never run.  Fix this.
-  // Might be easiest to just use base::Callback.
   PostTask(FROM_HERE, "StartImpl",
            method_factory_.NewRunnableMethod(
                &SyncScheduler::StartImpl, mode, callback));
@@ -241,19 +243,18 @@ void SyncScheduler::WatchConnectionManager() {
   scm->AddListener(this);
 }
 
-void SyncScheduler::StartImpl(Mode mode, ModeChangeCallback* callback) {
+void SyncScheduler::StartImpl(Mode mode, const base::Closure& callback) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   SVLOG(2) << "In StartImpl with mode " << GetModeString(mode);
 
-  scoped_ptr<ModeChangeCallback> scoped_callback(callback);
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   DCHECK(!session_context_->account_name().empty());
   DCHECK(syncer_.get());
   Mode old_mode = mode_;
   mode_ = mode;
   AdjustPolling(NULL);  // Will kick start poll timer if needed.
-  if (scoped_callback.get())
-    scoped_callback->Run();
+  if (!callback.is_null())
+    callback.Run();
 
   if (old_mode != mode_) {
     // We just changed our mode. See if there are any pending jobs that we could
@@ -343,7 +344,8 @@ void SyncScheduler::InitOrCoalescePendingJob(const SyncSessionJob& job) {
         s->delegate(), s->source(), s->routing_info(), s->workers()));
 
     SyncSessionJob new_job(SyncSessionJob::NUDGE, job.scheduled_start,
-        make_linked_ptr(session.release()), false, job.from_here);
+                           make_linked_ptr(session.release()),
+                           false, base::Closure(), job.from_here);
     pending_nudge_.reset(new SyncSessionJob(new_job));
 
     return;
@@ -391,7 +393,8 @@ void SyncScheduler::SaveJob(const SyncSessionJob& job) {
     SyncSession* s(new SyncSession(session_context_.get(), this,
         old->source(), old->routing_info(), old->workers()));
     SyncSessionJob new_job(job.purpose, TimeTicks::Now(),
-                           make_linked_ptr(s), false, job.from_here);
+                           make_linked_ptr(s), false, base::Closure(),
+                           job.from_here);
     wait_interval_->pending_configure_job.reset(new SyncSessionJob(new_job));
   } // drop the rest.
   // TODO(sync): Is it okay to drop the rest?  It's weird that
@@ -415,11 +418,12 @@ void SyncScheduler::ScheduleClearUserData() {
                &SyncScheduler::ScheduleClearUserDataImpl));
 }
 
-void SyncScheduler::ScheduleCleanupDisabledTypes() {
+void SyncScheduler::ScheduleCleanupDisabledTypes(
+    const base::Closure& callback) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   PostTask(FROM_HERE, "ScheduleCleanupDisabledTypes",
            method_factory_.NewRunnableMethod(
-               &SyncScheduler::ScheduleCleanupDisabledTypesImpl));
+               &SyncScheduler::ScheduleCleanupDisabledTypesImpl, callback));
 }
 
 void SyncScheduler::ScheduleNudge(
@@ -463,14 +467,15 @@ void SyncScheduler::ScheduleClearUserDataImpl() {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   ScheduleSyncSessionJob(
       TimeDelta::FromSeconds(0), SyncSessionJob::CLEAR_USER_DATA,
-      CreateSyncSession(SyncSourceInfo()), FROM_HERE);
+      CreateSyncSession(SyncSourceInfo()), base::Closure(), FROM_HERE);
 }
 
-void SyncScheduler::ScheduleCleanupDisabledTypesImpl() {
+void SyncScheduler::ScheduleCleanupDisabledTypesImpl(
+    const base::Closure& callback) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   ScheduleSyncSessionJob(
       TimeDelta::FromSeconds(0), SyncSessionJob::CLEANUP_DISABLED_TYPES,
-      CreateSyncSession(SyncSourceInfo()), FROM_HERE);
+      CreateSyncSession(SyncSourceInfo()), callback, FROM_HERE);
 }
 
 void SyncScheduler::ScheduleNudgeImpl(
@@ -493,7 +498,7 @@ void SyncScheduler::ScheduleNudgeImpl(
   SyncSession* session(CreateSyncSession(info));
   SyncSessionJob job(SyncSessionJob::NUDGE, TimeTicks::Now() + delay,
                      make_linked_ptr(session), is_canary_job,
-                     nudge_location);
+                     base::Closure(), nudge_location);
 
   session = NULL;
   if (!ShouldRunJob(job))
@@ -523,7 +528,7 @@ void SyncScheduler::ScheduleNudgeImpl(
 
   // TODO(lipalani) - pass the job itself to ScheduleSyncSessionJob.
   ScheduleSyncSessionJob(delay, SyncSessionJob::NUDGE, job.session.release(),
-      nudge_location);
+                         base::Closure(), nudge_location);
 }
 
 // Helper to extract the routing info and workers corresponding to types in
@@ -600,7 +605,8 @@ void SyncScheduler::ScheduleConfigImpl(
               routing_info, std::string())),
       routing_info, workers);
   ScheduleSyncSessionJob(TimeDelta::FromSeconds(0),
-    SyncSessionJob::CONFIGURATION, session, FROM_HERE);
+                         SyncSessionJob::CONFIGURATION,
+                         session, base::Closure(), FROM_HERE);
 }
 
 const char* SyncScheduler::GetModeString(SyncScheduler::Mode mode) {
@@ -640,6 +646,7 @@ void SyncScheduler::ScheduleSyncSessionJob(
     const base::TimeDelta& delay,
     SyncSessionJob::SyncSessionJobPurpose purpose,
     sessions::SyncSession* session,
+    const base::Closure& on_success,
     const tracked_objects::Location& from_here) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   SVLOG_LOC(from_here, 2)
@@ -648,7 +655,7 @@ void SyncScheduler::ScheduleSyncSessionJob(
       << " job and " << delay.InMilliseconds() << " ms delay";
 
   SyncSessionJob job(purpose, TimeTicks::Now() + delay,
-                     make_linked_ptr(session), false, from_here);
+                     make_linked_ptr(session), false, on_success, from_here);
   if (purpose == SyncSessionJob::NUDGE) {
     SVLOG_LOC(from_here, 2) << "Resetting pending_nudge";
     DCHECK(!pending_nudge_.get() || pending_nudge_->session.get() == session);
@@ -782,6 +789,8 @@ void SyncScheduler::FinishSyncSessionJob(const SyncSessionJob& job) {
 
   SVLOG(2) << "Updating the next polling time after SyncMain";
   ScheduleNextSync(job);
+  if (!job.on_success.is_null())
+    job.on_success.Run();
 }
 
 void SyncScheduler::ScheduleNextSync(const SyncSessionJob& old_job) {
@@ -910,7 +919,8 @@ void SyncScheduler::HandleConsecutiveContinuationError(
     SyncSession* s(new SyncSession(session_context_.get(), this,
         old->source(), old->routing_info(), old->workers()));
     SyncSessionJob job(old_job.purpose, TimeTicks::Now() + length,
-                        make_linked_ptr(s), false, FROM_HERE);
+                       make_linked_ptr(s), false, base::Closure(),
+                       FROM_HERE);
     wait_interval_->pending_configure_job.reset(new SyncSessionJob(job));
   } else {
     // We are not in configuration mode. So wait_interval's pending job
@@ -1006,6 +1016,8 @@ SyncSession* SyncScheduler::CreateSyncSession(const SyncSourceInfo& source) {
   ModelSafeRoutingInfo routes;
   std::vector<ModelSafeWorker*> workers;
   session_context_->registrar()->GetModelSafeRoutingInfo(&routes);
+  VLOG(2) << "Creating sync session with routes "
+          << ModelSafeRoutingInfoToString(routes);
   session_context_->registrar()->GetWorkers(&workers);
   SyncSourceInfo info(source);
 
@@ -1023,7 +1035,7 @@ void SyncScheduler::PollTimerCallback() {
   SyncSourceInfo info(GetUpdatesCallerInfo::PERIODIC, types_with_payloads);
   SyncSession* s = CreateSyncSession(info);
   ScheduleSyncSessionJob(TimeDelta::FromSeconds(0), SyncSessionJob::POLL, s,
-      FROM_HERE);
+                         base::Closure(), FROM_HERE);
 }
 
 void SyncScheduler::Unthrottle() {