Overview Tray Button should not be visible on login screen

ash/system/overview/overview_button_tray.cc

Index: ash/system/overview/overview_button_tray.cc
diff --git a/ash/system/overview/overview_button_tray.cc b/ash/system/overview/overview_button_tray.cc
index 4ca41668d8f050713dab76be5f83bf45806d7add..3a9fff87dadb5407422e2d3e1501d6ed03df04b9 100644
--- a/ash/system/overview/overview_button_tray.cc
+++ b/ash/system/overview/overview_button_tray.cc
@@ -6,6 +6,7 @@
 
 #include "ash/shelf/shelf_types.h"
 #include "ash/shell.h"
+#include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/tray_utils.h"
 #include "ash/wm/overview/window_selector_controller.h"
 #include "grit/ash_resources.h"
@@ -41,7 +42,7 @@ OverviewButtonTray::OverviewButtonTray(
   SetIconBorderForShelfAlignment();
   tray_container()->AddChildView(icon_);
 
-  SetVisible(Shell::GetInstance()->IsMaximizeModeWindowManagerEnabled());
+  SetIconVisibility(Shell::GetInstance()->IsMaximizeModeWindowManagerEnabled());
 
   Shell::GetInstance()->AddShellObserver(this);
 }
@@ -56,11 +57,11 @@ bool OverviewButtonTray::PerformAction(const ui::Event& event) {
 }
 
 void OverviewButtonTray::OnMaximizeModeStarted() {
-  SetVisible(true);
+  SetIconVisibility(true);

[flackr, 2014/03/28 16:56:40]

nit: Comment what argument is for clarity: i.e.
SetIconVisibility(/* maximize_mode_enabled */ true);

[jonross, 2014/03/28 19:39:01]

Done.

 }
 
 void OverviewButtonTray::OnMaximizeModeEnded() {
-  SetVisible(false);
+  SetIconVisibility(false);

[flackr, 2014/03/28 16:56:40]

And here.

[jonross, 2014/03/28 19:39:01]

Done.

 }
 
 bool OverviewButtonTray::ClickedOutsideBubble() {
@@ -103,4 +104,14 @@ void OverviewButtonTray::SetIconBorderForShelfAlignment() {
   }
 }
 
+void OverviewButtonTray::SetIconVisibility(bool maximize_mode_enabled) {

[flackr, 2014/03/28 16:56:40]

nit: Since this doesn't just use maximize_mode_enabled, call this
UpdateIconVisibility.

[jonross, 2014/03/28 19:39:01]

Done.

+  SetVisible(maximize_mode_enabled &&
+             Shell::GetInstance()->window_selector_controller()->CanSelect());
+}
+
+void OverviewButtonTray::UpdateAfterLoginStatusChange(
+    user::LoginStatus status) {
+  SetIconVisibility(Shell::GetInstance()->IsMaximizeModeWindowManagerEnabled());
+}
+
 }  // namespace ash