Attempt 2 at: Fixes crash that occured because NativeViewHostAura::Detach was not

ui/views/controls/native/native_view_host.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_CONTROLS_NATIVE_NATIVE_VIEW_HOST_H_
 #define UI_VIEWS_CONTROLS_NATIVE_NATIVE_VIEW_HOST_H_
 
 #include <string>
 
 #include "ui/gfx/native_widget_types.h"
@@ skipping 77 matching lines @@
   virtual void ViewHierarchyChanged(bool is_add,
                                     View* parent,
                                     View* child) OVERRIDE;
   virtual std::string GetClassName() const OVERRIDE;
 
  private:
   // Detach the native view. |destroyed| is true if the native view is
   // detached because it's being destroyed, or false otherwise.
   void Detach(bool destroyed);
 
+  // Invokes ViewRemoved() on the FocusManager for all the child Widgets of our
+  // NativeView. This is used when detaching to ensure the FocusManager doesn't
+  // have a reference to a View that is no longer reachable.
+  void ClearFocus();
+
   // The attached native view. There is exactly one native_view_ attached.
   gfx::NativeView native_view_;
 
   // A platform-specific wrapper that does the OS-level manipulation of the
   // attached gfx::NativeView.
   scoped_ptr<NativeViewHostWrapper> native_wrapper_;
 
   // The preferred size of this View
   gfx::Size preferred_size_;
 
   // True if the native view is being resized using the fast method described
   // in the setter/accessor above.
   bool fast_resize_;
 
   // Value of |fast_resize_| during the last call to Layout.
   bool fast_resize_at_last_layout_;
 
   // The view that should be given focus when this NativeViewHost is focused.
   View* focus_view_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeViewHost);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_NATIVE_NATIVE_VIEW_HOST_H_