sync: Remove SyncSessionJob destruction observer

This code was used to track down crbug.com/165561.  It hasn't detected
any crashes since M26 was branched.  It's safe to remove it now.

BUG=165561


Review URL: https://chromiumcodereview.appspot.com/12603010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@188778 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 9 insertions, 47 deletions

diff --git a/sync/engine/sync_scheduler_impl.cc b/sync/engine/sync_scheduler_impl.cc
index 8dd3ee6..0f55c5f 100644
--- a/sync/engine/sync_scheduler_impl.cc
+++ b/sync/engine/sync_scheduler_impl.cc
@@ -184,11 +184,6 @@ SyncSchedulerImpl::~SyncSchedulerImpl() {
   StopImpl(base::Closure());
 }
 
-void SyncSchedulerImpl::OnJobDestroyed(SyncSessionJob* job) {
-  // TODO(tim): Bug 165561 investigation.
-  CHECK(!pending_nudge_ || pending_nudge_ != job);
-}
-
 void SyncSchedulerImpl::OnCredentialsUpdated() {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
 
@@ -327,7 +322,6 @@ bool SyncSchedulerImpl::ScheduleConfiguration(
         TimeTicks::Now(),
         session.Pass(),
         params));
-    job->set_destruction_observer(weak_ptr_factory_.GetWeakPtr());
     bool succeeded = DoSyncSessionJob(job.Pass(), NORMAL_PRIORITY);
 
     // If we failed, the job would have been saved as the pending configure
@@ -491,7 +485,7 @@ void SyncSchedulerImpl::HandleSaveJobDecision(scoped_ptr<SyncSessionJob> job) {
   if (wait_interval_.get() && !wait_interval_->pending_configure_job) {
     // This job should be made the new canary.
     if (is_nudge) {
-      set_pending_nudge(job_to_save.get());
+      pending_nudge_ = job_to_save.get();
     } else {
       SDVLOG(2) << "Saving a configuration job";
       DCHECK_EQ(job->purpose(), SyncSessionJob::CONFIGURATION);
@@ -503,7 +497,7 @@ void SyncSchedulerImpl::HandleSaveJobDecision(scoped_ptr<SyncSessionJob> job) {
       if (pending_nudge_) {
         // Pre-empt the nudge canary and abandon the old nudge (owned by task).
         unscheduled_nudge_storage_ = pending_nudge_->CloneAndAbandon();
-        set_pending_nudge(unscheduled_nudge_storage_.get());
+        pending_nudge_ = unscheduled_nudge_storage_.get();
       }
       wait_interval_->pending_configure_job = job_to_save.get();
     }
@@ -520,7 +514,7 @@ void SyncSchedulerImpl::HandleSaveJobDecision(scoped_ptr<SyncSessionJob> job) {
   DCHECK(is_nudge);
   // There may or may not be a pending_configure_job. Either way this nudge
   // is unschedulable.
-  set_pending_nudge(job_to_save.get());
+  pending_nudge_ = job_to_save.get();
   unscheduled_nudge_storage_ = job_to_save.Pass();
 }
 
@@ -599,7 +593,6 @@ void SyncSchedulerImpl::ScheduleNudgeImpl(
       TimeTicks::Now() + delay,
       CreateSyncSession(info).Pass(),
       ConfigurationParams()));
-  job->set_destruction_observer(weak_ptr_factory_.GetWeakPtr());
   JobProcessDecision decision = DecideOnJob(*job, NORMAL_PRIORITY);
   SDVLOG(2) << "Should run "
             << SyncSessionJob::GetPurposeString(job->purpose())
@@ -709,7 +702,7 @@ void SyncSchedulerImpl::ScheduleSyncSessionJob(
     SDVLOG_LOC(loc, 2) << "Resetting pending_nudge to ";
     DCHECK(!pending_nudge_ || pending_nudge_->session() ==
            job->session());
-    set_pending_nudge(job.get());
+    pending_nudge_ = job.get();
   }
 
   PostDelayedTask(loc, "DoSyncSessionJob",
@@ -807,11 +800,6 @@ bool SyncSchedulerImpl::FinishSyncSessionJob(scoped_ptr<SyncSessionJob> job,
   return succeeded;
 }
 
-void SyncSchedulerImpl::set_pending_nudge(SyncSessionJob* job) {
-  job->set_destruction_observer(weak_ptr_factory_.GetWeakPtr());
-  pending_nudge_ = job;
-}
-
 void SyncSchedulerImpl::ScheduleNextSync(
     scoped_ptr<SyncSessionJob> finished_job, bool succeeded) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
@@ -835,7 +823,7 @@ void SyncSchedulerImpl::ScheduleNextSync(
     // any job through while in WaitInterval::THROTTLED).
     scoped_ptr<SyncSessionJob> clone = finished_job->Clone();
     if (clone->purpose() == SyncSessionJob::NUDGE)
-      set_pending_nudge(clone.get());
+      pending_nudge_ = clone.get();
     else if (clone->purpose() == SyncSessionJob::CONFIGURATION)
       wait_interval_->pending_configure_job = clone.get();
     else
@@ -871,7 +859,7 @@ void SyncSchedulerImpl::ScheduleNextSync(
     DCHECK(!pending_nudge_);
 
     scoped_ptr<SyncSessionJob> new_job = finished_job->Clone();
-    set_pending_nudge(new_job.get());
+    pending_nudge_ = new_job.get();
     RestartWaiting(new_job.Pass());
   } else {
     // Either this is the first failure or a consecutive failure after our
@@ -949,7 +937,7 @@ void SyncSchedulerImpl::HandleContinuationError(
     // should be null.
     DCHECK(wait_interval_->pending_configure_job == NULL);
     DCHECK(!pending_nudge_);
-    set_pending_nudge(new_job.get());
+    pending_nudge_ = new_job.get();
   }
 
   RestartWaiting(new_job.Pass());
@@ -1017,7 +1005,7 @@ scoped_ptr<SyncSessionJob> SyncSchedulerImpl::TakePendingJobForCurrentMode() {
   } else if (mode_ == NORMAL_MODE && pending_nudge_) {
     SDVLOG(2) << "Found pending nudge job";
     candidate = pending_nudge_->CloneAndAbandon();
-    set_pending_nudge(candidate.get());
+    pending_nudge_ = candidate.get();
     unscheduled_nudge_storage_.reset();
   }
   // If we took a job and there's a wait interval, we took the pending canary.
@@ -1047,7 +1035,6 @@ void SyncSchedulerImpl::PollTimerCallback() {
                                                     TimeTicks::Now(),
                                                     s.Pass(),
                                                     ConfigurationParams()));
-  job->set_destruction_observer(weak_ptr_factory_.GetWeakPtr());
   ScheduleSyncSessionJob(FROM_HERE, job.Pass());
 }
 
diff --git a/sync/engine/sync_scheduler_impl.h b/sync/engine/sync_scheduler_impl.h
index 7eba048..7190bdf6 100644
--- a/sync/engine/sync_scheduler_impl.h
+++ b/sync/engine/sync_scheduler_impl.h
@@ -33,9 +33,7 @@ namespace syncer {
 
 class BackoffDelayProvider;
 
-class SYNC_EXPORT_PRIVATE SyncSchedulerImpl :
-    public SyncScheduler,
-    public SyncSessionJob::DestructionObserver {
+class SYNC_EXPORT_PRIVATE SyncSchedulerImpl : public SyncScheduler {
  public:
   // |name| is a display string to identify the syncer thread.  Takes
   // |ownership of |syncer| and |delay_provider|.
@@ -81,9 +79,6 @@ class SYNC_EXPORT_PRIVATE SyncSchedulerImpl :
   virtual void OnSyncProtocolError(
       const sessions::SyncSessionSnapshot& snapshot) OVERRIDE;
 
-  // SyncSessionJob::DestructionObserver implementation.
-  virtual void OnJobDestroyed(SyncSessionJob* job) OVERRIDE;
-
  private:
   enum JobProcessDecision {
     // Indicates we should continue with the current job.
@@ -273,8 +268,6 @@ class SYNC_EXPORT_PRIVATE SyncSchedulerImpl :
 
   virtual void OnActionableError(const sessions::SyncSessionSnapshot& snapshot);
 
-  void set_pending_nudge(SyncSessionJob* job);
-
   base::WeakPtrFactory<SyncSchedulerImpl> weak_ptr_factory_;
 
   // A second factory specially for weak_handle_this_, to allow the handle
diff --git a/sync/engine/sync_session_job.cc b/sync/engine/sync_session_job.cc
index f18e010..f0d0d33 100644
--- a/sync/engine/sync_session_job.cc
+++ b/sync/engine/sync_session_job.cc
@@ -8,8 +8,6 @@
 namespace syncer {
 
 SyncSessionJob::~SyncSessionJob() {
-  if (destruction_observer_)
-    destruction_observer_->OnJobDestroyed(this);
 }
 
 SyncSessionJob::SyncSessionJob(
@@ -24,11 +22,6 @@ SyncSessionJob::SyncSessionJob(
       finished_(NOT_FINISHED) {
 }
 
-void SyncSessionJob::set_destruction_observer(
-    const base::WeakPtr<DestructionObserver>& destruction_observer) {
-  destruction_observer_ = destruction_observer;
-}
-
 #define ENUM_CASE(x) case x: return #x; break;
 const char* SyncSessionJob::GetPurposeString(SyncSessionJob::Purpose purpose) {
   switch (purpose) {
diff --git a/sync/engine/sync_session_job.h b/sync/engine/sync_session_job.h
index b57f227..33d2171 100644
--- a/sync/engine/sync_session_job.h
+++ b/sync/engine/sync_session_job.h
@@ -31,13 +31,6 @@ class SYNC_EXPORT_PRIVATE SyncSessionJob {
     CONFIGURATION,
   };
 
-  // This class exists to inform an interested party about the destruction of
-  // a SyncSessionJob.
-  class SYNC_EXPORT_PRIVATE DestructionObserver {
-   public:
-    virtual void OnJobDestroyed(SyncSessionJob* job) = 0;
-  };
-
   SyncSessionJob(Purpose purpose,
                  base::TimeTicks start,
                  scoped_ptr<sessions::SyncSession> session,
@@ -84,8 +77,6 @@ class SYNC_EXPORT_PRIVATE SyncSessionJob {
   SyncerStep end_step() const;
   ConfigurationParams config_params() const;
 
-  void set_destruction_observer(
-      const base::WeakPtr<DestructionObserver>& observer);
  private:
   // A SyncSessionJob can be in one of these three states, controlled by the
   // Finish() function, see method comments.
@@ -111,8 +102,6 @@ class SYNC_EXPORT_PRIVATE SyncSessionJob {
   // all requisite steps given |purpose_| without being preempted.
   FinishedState finished_;
 
-  base::WeakPtr<DestructionObserver> destruction_observer_;
-
   DISALLOW_COPY_AND_ASSIGN(SyncSessionJob);
 };