Rename Launcher to Shelf.

ash/system/tray/system_tray.cc

Index: ash/system/tray/system_tray.cc
diff --git a/ash/system/tray/system_tray.cc b/ash/system/tray/system_tray.cc
index cee88472837d7930d5fb8a47e11f97a513d3b16f..48d90c51e27781aa5d960d0c9b8ad996a2ae4d34 100644
--- a/ash/system/tray/system_tray.cc
+++ b/ash/system/tray/system_tray.cc
@@ -342,8 +342,8 @@ void SystemTray::SetHideNotifications(bool hide_notifications) {
   hide_notifications_ = hide_notifications;
 }
 
-bool SystemTray::ShouldShowLauncher() const {
-  return system_bubble_.get() && system_bubble_->bubble()->ShouldShowLauncher();
+bool SystemTray::ShouldShowShelf() const {
+  return system_bubble_.get() && system_bubble_->bubble()->ShouldShowShelf();
 }
 
 bool SystemTray::HasSystemBubble() const {
@@ -618,7 +618,7 @@ void SystemTray::SetShelfAlignment(ShelfAlignment alignment) {
 void SystemTray::AnchorUpdated() {
   if (notification_bubble_) {
     notification_bubble_->bubble_view()->UpdateBubble();
-    // Ensure that the notification buble is above the launcher/status area.
+    // Ensure that the notification buble is above the shelf/status area.
     notification_bubble_->bubble_view()->GetWidget()->StackAtTop();
     UpdateBubbleViewArrow(notification_bubble_->bubble_view());
   }