Use active state on touch start for tray icons

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 b56efa9404014e9974e2f2c07fedf520bb73a421..fc05ce10fc700b08c33c72bfdab6bb377d3a42af 100644
--- a/ash/system/overview/overview_button_tray.cc
+++ b/ash/system/overview/overview_button_tray.cc
@@ -40,12 +40,9 @@ OverviewButtonTray::OverviewButtonTray(StatusAreaWidget* status_area_widget)
       bundle.GetImageNamed(IDR_AURA_UBER_TRAY_OVERVIEW_MODE).ToImageSkia());
   SetIconBorderForShelfAlignment();
   tray_container()->AddChildView(icon_);
-
-  Shell::GetInstance()->AddShellObserver(this);
 }
 
 OverviewButtonTray::~OverviewButtonTray() {
-  Shell::GetInstance()->RemoveShellObserver(this);
 }
 
 void OverviewButtonTray::UpdateAfterLoginStatusChange(
@@ -54,16 +51,21 @@ void OverviewButtonTray::UpdateAfterLoginStatusChange(
 }
 
 bool OverviewButtonTray::PerformAction(const ui::Event& event) {
-  Shell::GetInstance()->window_selector_controller()->ToggleOverview();
+  WindowSelectorController* controller =
+      Shell::GetInstance()->window_selector_controller();
+  controller->ToggleOverview();
+  SetDrawBackgroundAsActive(controller->IsSelecting());
   return true;
 }
 
 void OverviewButtonTray::OnMaximizeModeStarted() {
   UpdateIconVisibility();
+  TrayBackgroundView::OnMaximizeModeStarted();
 }
 
 void OverviewButtonTray::OnMaximizeModeEnded() {
   UpdateIconVisibility();
+  TrayBackgroundView::OnMaximizeModeEnded();
 }
 
 bool OverviewButtonTray::ClickedOutsideBubble() {