Makes closing a fullscreen window refocus the window it came from.

content/browser/renderer_host/render_widget_host_view_aura.h

Index: content/browser/renderer_host/render_widget_host_view_aura.h
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.h b/content/browser/renderer_host/render_widget_host_view_aura.h
index 04d814c04a38e723d0c7083108e545c4bb6f0a15..fbfc5e396769e5ab2b4c8e4ef467440ba2c36dd9 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.h
+++ b/content/browser/renderer_host/render_widget_host_view_aura.h
@@ -24,6 +24,7 @@
 
 namespace aura {
 class CompositorLock;
+class WindowTracker;
 }
 
 namespace gfx {
@@ -385,6 +386,10 @@ class RenderWidgetHostViewAura
   // This lock is for waiting for a front surface to become available to draw.
   scoped_refptr<aura::CompositorLock> released_front_lock_;
 
+  // Used to track the state of the window we're created from. Only used when
+  // created fullscreen.
+  scoped_ptr<aura::WindowTracker> host_tracker_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewAura);
 };