Moves maintaining root_window_for_new_windows_ to Shell

ash/common/accelerators/accelerator_controller.cc

Index: ash/common/accelerators/accelerator_controller.cc
diff --git a/ash/common/accelerators/accelerator_controller.cc b/ash/common/accelerators/accelerator_controller.cc
index 52e33dd9981ed584f1f5d09879d93c634efba0bb..d80246553ca0171830ff48164906e42e2b1da545 100644
--- a/ash/common/accelerators/accelerator_controller.cc
+++ b/ash/common/accelerators/accelerator_controller.cc
@@ -41,6 +41,7 @@
 #include "ash/common/wm_window.h"
 #include "ash/resources/vector_icons/vector_icons.h"
 #include "ash/root_window_controller.h"
+#include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
@@ -211,7 +212,7 @@ void HandleShowKeyboardOverlay() {
 }
 
 bool CanHandleShowMessageCenterBubble() {
-  WmWindow* target_root = WmShell::Get()->GetRootWindowForNewWindows();
+  WmWindow* target_root = Shell::GetInstance()->GetRootWindowForNewWindows();
   StatusAreaWidget* status_area_widget =
       WmShelf::ForWindow(target_root)->shelf_widget()->status_area_widget();
   return status_area_widget &&
@@ -220,7 +221,7 @@ bool CanHandleShowMessageCenterBubble() {
 
 void HandleShowMessageCenterBubble() {
   base::RecordAction(UserMetricsAction("Accel_Show_Message_Center_Bubble"));
-  WmWindow* target_root = WmShell::Get()->GetRootWindowForNewWindows();
+  WmWindow* target_root = Shell::GetInstance()->GetRootWindowForNewWindows();
   StatusAreaWidget* status_area_widget =
       WmShelf::ForWindow(target_root)->shelf_widget()->status_area_widget();
   if (status_area_widget) {
@@ -394,7 +395,9 @@ void HandleShowStylusTools() {
   base::RecordAction(UserMetricsAction("Accel_Show_Stylus_Tools"));
 
   RootWindowController* root_window_controller =
-      WmShell::Get()->GetRootWindowForNewWindows()->GetRootWindowController();
+      Shell::GetInstance()
+          ->GetRootWindowForNewWindows()
+          ->GetRootWindowController();
   PaletteTray* palette_tray =
       root_window_controller->GetShelf()->GetStatusAreaWidget()->palette_tray();
   palette_tray->ShowPalette();