Rename MaximizeMode to TabletMode

ash/system/rotation/tray_rotation_lock.h

Index: ash/system/rotation/tray_rotation_lock.h
diff --git a/ash/system/rotation/tray_rotation_lock.h b/ash/system/rotation/tray_rotation_lock.h
index 1dbe7a7fc3816eaf294df2e05f39cf675258e9fa..fdfc5a2c317946aa111cec1ff891ee4b53a3bb6c 100644
--- a/ash/system/rotation/tray_rotation_lock.h
+++ b/ash/system/rotation/tray_rotation_lock.h
@@ -32,8 +32,8 @@ class ASH_EXPORT TrayRotationLock
   views::View* CreateDefaultView(LoginStatus status) override;
 
   // ShellObserver:
-  void OnMaximizeModeStarted() override;
-  void OnMaximizeModeEnded() override;
+  void OnTabletModeStarted() override;
+  void OnTabletModeEnded() override;
 
   // TrayImageItem:
   void DestroyTrayView() override;
@@ -48,7 +48,7 @@ class ASH_EXPORT TrayRotationLock
   // Update tray image based on whether user rotation lock is enabled.
   void UpdateTrayImage();
 
-  // True if |on_primary_display_|, maximize mode is enabled.
+  // True if |on_primary_display_|, tablet mode is enabled.
   bool ShouldBeVisible();
 
   // True if this is owned by a SystemTray on the primary display.