Moves maintaining root_window_for_new_windows_ to Shell

chrome/browser/ui/window_sizer/window_sizer_ash_unittest.cc

Index: chrome/browser/ui/window_sizer/window_sizer_ash_unittest.cc
diff --git a/chrome/browser/ui/window_sizer/window_sizer_ash_unittest.cc b/chrome/browser/ui/window_sizer/window_sizer_ash_unittest.cc
index aee502ab1f82e7628a1f915a31047f351dbfeb3c..1280af380ef12745cf890d36b80ed77725babb95 100644
--- a/chrome/browser/ui/window_sizer/window_sizer_ash_unittest.cc
+++ b/chrome/browser/ui/window_sizer/window_sizer_ash_unittest.cc
@@ -824,7 +824,8 @@ TEST_F(WindowSizerAshTest, DefaultBoundsInTargetDisplay) {
 
   // By default windows are placed on the primary display.
   ash::WmWindow* first_root = ash::WmShell::Get()->GetAllRootWindows()[0];
-  EXPECT_EQ(first_root, ash::WmShell::Get()->GetRootWindowForNewWindows());
+  EXPECT_EQ(first_root,
+            ash::Shell::GetInstance()->GetRootWindowForNewWindows());
   gfx::Rect bounds;
   ui::WindowShowState show_state;
   WindowSizer::GetBrowserWindowBoundsAndShowState(std::string(), gfx::Rect(),