Revert 235267 "Fix crash in WebContentsViewAura::WindowObserver ..."

trunk/src/content/browser/web_contents/web_contents_view_aura.cc

Index: trunk/src/content/browser/web_contents/web_contents_view_aura.cc
===================================================================
--- trunk/src/content/browser/web_contents/web_contents_view_aura.cc	(revision 235276)
+++ trunk/src/content/browser/web_contents/web_contents_view_aura.cc	(working copy)
@@ -799,11 +799,6 @@
       window->GetDispatcher()->RemoveRootWindowObserver(this);
 #if defined(OS_WIN)
       window->GetRootWindow()->RemoveObserver(this);
-
-      const aura::Window::Windows& root_children =
-          window->GetRootWindow()->children();
-      for (size_t i = 0; i < root_children.size(); ++i)
-        root_children[i]->RemoveObserver(this);
 #endif
     }
   }