chromeos: Rename ash::WmShelf to Shelf

ash/system/virtual_keyboard/virtual_keyboard_tray.cc

Index: ash/system/virtual_keyboard/virtual_keyboard_tray.cc
diff --git a/ash/system/virtual_keyboard/virtual_keyboard_tray.cc b/ash/system/virtual_keyboard/virtual_keyboard_tray.cc
index 7dd3599a8a399b39f0a1eb649963fbdd57eeb17d..ff6dfe85eff2a57164e18467bfd1e917dabe1495 100644
--- a/ash/system/virtual_keyboard/virtual_keyboard_tray.cc
+++ b/ash/system/virtual_keyboard/virtual_keyboard_tray.cc
@@ -8,8 +8,8 @@
 
 #include "ash/keyboard/keyboard_ui.h"
 #include "ash/resources/vector_icons/vector_icons.h"
+#include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_constants.h"
-#include "ash/shelf/wm_shelf.h"
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/tray/tray_constants.h"
@@ -25,10 +25,8 @@
 
 namespace ash {
 
-VirtualKeyboardTray::VirtualKeyboardTray(WmShelf* wm_shelf)
-    : TrayBackgroundView(wm_shelf),
-      icon_(new views::ImageView),
-      wm_shelf_(wm_shelf) {
+VirtualKeyboardTray::VirtualKeyboardTray(Shelf* shelf)
+    : TrayBackgroundView(shelf), icon_(new views::ImageView), shelf_(shelf) {
   SetInkDropMode(InkDropMode::ON);
 
   gfx::ImageSkia image =
@@ -67,7 +65,7 @@ void VirtualKeyboardTray::ClickedOutsideBubble() {}
 
 bool VirtualKeyboardTray::PerformAction(const ui::Event& event) {
   const int64_t display_id =
-      wm_shelf_->GetWindow()->GetDisplayNearestWindow().id();
+      shelf_->GetWindow()->GetDisplayNearestWindow().id();
   Shell::Get()->keyboard_ui()->ShowInDisplay(display_id);
   // Normally, active status is set when virtual keyboard is shown/hidden,
   // however, showing virtual keyboard happens asynchronously and, especially