Allow a Views client to provide a default frameview for window widgets.

ash/shell.h

Index: ash/shell.h
===================================================================
--- ash/shell.h	(revision 117091)
+++ ash/shell.h	(working copy)
@@ -27,6 +27,10 @@
 class Rect;
 class Size;
 }
+namespace views {
+class NonClientFrameView;
+class Widget;
+}
 
 namespace ash {
 
@@ -84,6 +88,11 @@
   // See enum WindowMode for details.
   bool IsWindowModeCompact() const { return window_mode_ == COMPACT_MODE; }
 
+  // Creates a default views::NonClientFrameView for use by windows in the
+  // Ash environment.
+  views::NonClientFrameView* CreateDefaultNonClientFrameView(
+      views::Widget* widget);
+
   AcceleratorController* accelerator_controller() {
     return accelerator_controller_.get();
   }