[Mac] Remove dead underlayImage_ from GradientButtonCell.

chrome/browser/cocoa/gradient_button_cell.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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_COCOA_CHROMIUM_BUTTON_CELL_H_
 #define CHROME_BROWSER_COCOA_CHROMIUM_BUTTON_CELL_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/scoped_nsobject.h"
 
@@ skipping 18 matching lines @@
 @interface GradientButtonCell : NSButtonCell {
  @private
   // Custom drawing means we need to perform our own mouse tracking if
   // the cell is setShowsBorderOnlyWhileMouseInside:YES.
   BOOL isMouseInside_;
   scoped_nsobject<NSTrackingArea> trackingArea_;
   BOOL shouldTheme_;
   CGFloat hoverAlpha_;  // 0-1. Controls the alpha during mouse hover
   NSTimeInterval lastHoverUpdate_;
   scoped_nsobject<NSGradient> gradient_;
-  scoped_nsobject<NSImage> underlayImage_;
 }
 
 // Turn off theming.  Temporary work-around.
 - (void)setShouldTheme:(BOOL)shouldTheme;
 
 - (void)drawBorderAndFillForTheme:(ThemeProvider*)themeProvider
                       controlView:(NSView*)controlView
                         innerPath:(NSBezierPath*)innerPath
               showClickedGradient:(BOOL)showClickedGradient
             showHighlightGradient:(BOOL)showHighlightGradient
                        hoverAlpha:(CGFloat)hoverAlpha
                            active:(BOOL)active
                         cellFrame:(NSRect)cellFrame
                   defaultGradient:(NSGradient*)defaultGradient;
 
-// An image to underlay beneath the existing image; not themed. May be nil.
-- (NSImage*)underlayImage;
-- (void)setUnderlayImage:(NSImage*)image;
-
 // Let the view know when the mouse moves in and out. A timer will update
 // the current hoverAlpha_ based on these events.
 - (void)setMouseInside:(BOOL)flag animate:(BOOL)animate;
 
 // Gets the path which tightly bounds the outside of the button. This is needed
 // to produce images of clear buttons which only include the area inside, since
 // the background of the button is drawn by someone else.
 - (NSBezierPath*)clipPathForFrame:(NSRect)cellFrame
                            inView:(NSView*)controlView;
 
 @property(assign, nonatomic)CGFloat hoverAlpha;
 @end
 
 @interface GradientButtonCell(TestingAPI)
 - (BOOL)isMouseInside;
 @end
 
 #endif  // CHROME_BROWSER_COCOA_CHROMIUM_BUTTON_CELL_H_