mash: Convert FocusCycler to wm common types and move to //ash/common

ash/aura/wm_window_aura.cc

Index: ash/aura/wm_window_aura.cc
diff --git a/ash/aura/wm_window_aura.cc b/ash/aura/wm_window_aura.cc
index 4c2d74f0e514d54dafb7be7045440eb12c2c3370..6fc13e4a1d1ec0db4795d53d7a1489bb0a6a748a 100644
--- a/ash/aura/wm_window_aura.cc
+++ b/ash/aura/wm_window_aura.cc
@@ -514,9 +514,13 @@ void WmWindowAura::Show() {
   window_->Show();
 }
 
+views::Widget* WmWindowAura::GetWidget() {
+  return views::Widget::GetWidgetForNativeView(window_);
+}
+
 void WmWindowAura::CloseWidget() {

[msw, 2016/06/16 23:57:44]

nit: Remove this and inline GetWidget()->Close() for the one caller.

[James Cook, 2016/06/17 03:39:29]

I'm going to keep this, since there is a difference in CloseWidget() behavior
for WmWindowMus and I'm changing GetWidget() to GetInternalWidget().

-  DCHECK(views::Widget::GetWidgetForNativeView(window_));
-  views::Widget::GetWidgetForNativeView(window_)->Close();
+  DCHECK(GetWidget());
+  GetWidget()->Close();
 }
 
 bool WmWindowAura::IsFocused() const {