Use Titlebar instead of TitleBar consistently in panels code.

chrome/browser/ui/panels/panel_titlebar_view_cocoa.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_PANELS_PANEL_TITLEBAR_VIEW_COCOA_H_
 #define CHROME_BROWSER_UI_PANELS_PANEL_TITLEBAR_VIEW_COCOA_H_
 
 #import <Cocoa/Cocoa.h>
 
 #import "chrome/browser/ui/cocoa/tracking_area.h"
 
 @class CrTrackingArea;
 @class PanelWindowControllerCocoa;
 
-// A class that works as a custom title bar for Panels. It is placed on top of
-// the regular Cocoa title bar. We paint theme image on it, and it's
+// A class that works as a custom titlebar for Panels. It is placed on top of
+// the regular Cocoa titlebar. We paint theme image on it, and it's
 // the place for the close button, wrench button, page favicon, title label.
 // It also facilitates dragging and minimization of the panels, and changes
 // color as 'new activity' indicator.
 // One way to have custom titlebar would be to use NSBorderlessWindow,
 // but it seems to affect too many other behaviors (for example, it draws shadow
 // differently based on being key window) so it appears easier to simply overlay
 // the standard titlebar.
 
 @interface PanelTitlebarViewCocoa : NSView {
   IBOutlet PanelWindowControllerCocoa* controller_;
   NSButton* closeButton_;  // Created explicitly, not from NIB. Weak, destroyed
                            // when view is destroyed, as a subview.
   ScopedCrTrackingArea closeButtonTrackingArea_;
 }
 
   // Callback from Close button.
 - (void)onCloseButtonClick:(id)sender;
 
   // Attaches this view to the controller_'s window as a titlebar.
 - (void)attach;
 
-  // Should be called when size of the title bar changes.
+  // Should be called when size of the titlebar changes.
 - (void)updateCloseButtonLayout;
 
   // Accessor to Panel's controller.
 - (PanelWindowControllerCocoa*)controller;
 
 @end  // @interface PanelTitlebarView
 
 // Methods which are either only for testing, or only public for testing.
 @interface PanelTitlebarViewCocoa(TestingAPI)
 
 // Simulates click on a close button. Used to test panel closing.
 - (void)simulateCloseButtonClick;
 
 @end  // @interface PanelTitlebarViewCocoa(TestingAPI)
 
 #endif  // CHROME_BROWSER_UI_PANELS_PANEL_TITLEBAR_VIEW_COCOA_H_