Add missing include guards in Cocoa code.

chrome/browser/ui/cocoa/find_bar/find_bar_text_field_cell.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 CHROME_BROWSER_UI_COCOA_FIND_BAR_FIND_BAR_TEXT_FIELD_CELL_H_
+#define CHROME_BROWSER_UI_COCOA_FIND_BAR_FIND_BAR_TEXT_FIELD_CELL_H_
+
 #import <Cocoa/Cocoa.h>
 
 #import "chrome/browser/ui/cocoa/styled_text_field_cell.h"
 
 #include "base/mac/scoped_nsobject.h"
 
 // FindBarTextFieldCell extends StyledTextFieldCell to provide support for a
 // results label rooted at the right edge of the cell.
 @interface FindBarTextFieldCell : StyledTextFieldCell {
  @private
   // Set if there is a results label to display on the right side of the cell.
   base::scoped_nsobject<NSAttributedString> resultsString_;
 }
 
 // Sets the results label to the localized equivalent of "X of Y".
 - (void)setActiveMatch:(NSInteger)current of:(NSInteger)total;
 
 - (void)clearResults;
 
 - (NSString*)resultsString;
 
 @end
+
+#endif  // CHROME_BROWSER_UI_COCOA_FIND_BAR_FIND_BAR_TEXT_FIELD_CELL_H_