sync: reland scheduler ownership refactoring, now with less crash

sync/engine/sync_scheduler_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "base/test/test_timeouts.h"
@@ skipping 1115 matching lines @@
       zero(), NUDGE_SOURCE_LOCAL, ModelTypeSet(BOOKMARKS), FROM_HERE);
   // Should save the nudge for until after the server is reachable.
   MessageLoop::current()->RunAllPending();
 
   connection()->SetServerReachable();
   connection()->UpdateConnectionStatus();
   scheduler()->OnConnectionStatusChange();
   MessageLoop::current()->RunAllPending();
 }
 
+TEST_F(SyncSchedulerTest, ServerConnectionChangeDuringBackoff) {
+  UseMockDelayProvider();
+  EXPECT_CALL(*delay(), GetDelay(_))
+      .WillRepeatedly(Return(TimeDelta::FromMilliseconds(0)));
+
+  StartSyncScheduler(SyncScheduler::NORMAL_MODE);
+  connection()->SetServerNotReachable();
+  connection()->UpdateConnectionStatus();
+
+  EXPECT_CALL(*syncer(), SyncShare(_,_,_))
+    .WillOnce(DoAll(Invoke(sessions::test_util::SimulateConnectionFailure),
+                    Return(true)))
+    .WillOnce(DoAll(Invoke(sessions::test_util::SimulateSuccess),
+                    QuitLoopNowAction()));
+
+  scheduler()->ScheduleNudgeAsync(
+      zero(), NUDGE_SOURCE_LOCAL, ModelTypeSet(BOOKMARKS), FROM_HERE);
+
+  PumpLoop();  // Run the nudge, that will fail and schedule a quick retry.
+  ASSERT_TRUE(scheduler()->IsBackingOff());
+
+  // Before we run the scheduled canary, trigger a server connection change.
+  connection()->SetServerReachable();
+  connection()->UpdateConnectionStatus();
+  scheduler()->OnConnectionStatusChange();
+  MessageLoop::current()->RunAllPending();
+}
+
 }  // namespace syncer