Hook up TABLET_MODE switch to maximize_mode_controller

ash/wm/maximize_mode/maximize_mode_controller.h

Index: ash/wm/maximize_mode/maximize_mode_controller.h
diff --git a/ash/wm/maximize_mode/maximize_mode_controller.h b/ash/wm/maximize_mode/maximize_mode_controller.h
index b761a4d3d2dbb8cec81f2930733565cfaeead67a..9642573eb3666eaded895d7ebfdfce87e9ead23b 100644
--- a/ash/wm/maximize_mode/maximize_mode_controller.h
+++ b/ash/wm/maximize_mode/maximize_mode_controller.h
@@ -93,6 +93,7 @@ class ASH_EXPORT MaximizeModeController :
 
   // PowerManagerClient::Observer:
   void LidEventReceived(bool open, const base::TimeTicks& time) override;
+  void TabletModeEventReceived(bool on, const base::TimeTicks& time) override;
   void SuspendImminent() override;
   void SuspendDone(const base::TimeDelta& sleep_duration) override;
 #endif  // OS_CHROMEOS
@@ -169,6 +170,12 @@ class ASH_EXPORT MaximizeModeController :
   // Source for the current time in base::TimeTicks.
   std::unique_ptr<base::TickClock> tick_clock_;
 
+#if defined(OS_CHROMEOS)
+  // Set when tablet mode switch transitions from on to off. This is used to
+  // make HandleHingeRotation check whether we need to disable maximize mode.
+  bool tablet_mode_switch_was_on_;

[Daniel Erat, 2016/06/06 15:24:55]

it would probably be better to track "is_on" instead of "was_on". using
temporarily-set member variables to pass state from one method to another is
confusing: someone looking at the member has no idea *when* the switch was on.

[jcliang, 2016/06/06 16:48:36]

Yes I agree. This is improved after we remove lid_open_past_180_.

+#endif
+
   // Tracks when the lid is closed. Used to prevent entering maximize mode.
   bool lid_is_closed_;