Move FocusTracker to ui/.

ui/base/cocoa/focus_tracker.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/memory/scoped_nsobject.h"
 
 // A class that handles saving and restoring focus.  An instance of
 // this class snapshots the currently focused view when it is
 // constructed, and callers can use restoreFocus to return focus to
 // that view.  FocusTracker will not restore focus to views that are
 // no longer in the view hierarchy or are not in the correct window.
 
 @interface FocusTracker : NSObject {
  @private
   scoped_nsobject<NSView> focusedView_;
 }
 
 // |window| is the window that we are saving focus for.  This
 // method snapshots the currently focused view.
 - (id)initWithWindow:(NSWindow*)window;
 
 // Attempts to restore focus to the snapshotted view.  Returns YES if
 // focus was restored.  Will not restore focus if the view is no
 // longer in the view hierarchy under |window|.
 - (BOOL)restoreFocusInWindow:(NSWindow*)window;
 @end