Use native Cocoa tooltips instead of Mozilla's ToolTip class.

chrome/browser/renderer_host/render_widget_host_view_mac.h

 // Copyright (c) 2006-2008 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_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/scoped_nsobject.h"
@@ skipping 17 matching lines @@
 // RenderWidgetHostViewWin is both the view and the delegate. We split the roles
 // but that means that the view needs to own the delegate and will dispose of it
 // when it's removed from the view system.
 
 @interface RenderWidgetHostViewCocoa : BaseView <RenderWidgetHostViewMacOwner> {
  @private
   RenderWidgetHostViewMac* renderWidgetHostView_;
   BOOL canBeKeyView_;
   BOOL closeOnDeactivate_;
   scoped_ptr<RWHVMEditCommandHelper> editCommand_helper_;
+
+  // These are part of the magic tooltip code from WebKit's WebHTMLView:
+  id trackingRectOwner_;              // (not retained)
+  void *trackingRectUserData_;
+  NSTrackingRectTag lastToolTipTag_;
+  NSString* toolTip_;
 }
 
 - (void)setCanBeKeyView:(BOOL)can;
 - (void)setCloseOnDeactivate:(BOOL)b;
+- (void)setToolTipAtMousePoint:(NSString *)string;
 
 @end
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewMac
 //
 //  An object representing the "View" of a rendered web page. This object is
 //  responsible for displaying the content of the web page, and integrating with
 //  the Cocoa view system. It is the implementation of the RenderWidgetHostView
 //  that the cross-platform RenderWidgetHost object uses
@@ skipping 82 matching lines @@
 
   // The cursor for the page. This is passed up from the renderer.
   WebCursor current_cursor_;
 
   // Indicates if the page is loading.
   bool is_loading_;
 
   // true if the View is not visible.
   bool is_hidden_;
 
-  // Tooltips
   // The text to be shown in the tooltip, supplied by the renderer.
   std::wstring tooltip_text_;
-  // Used to display tooltips. We can't use the [NSView -setToolTip:] methods
-  // because we need to be able to show and hide the tooltip without the mouse
-  // leaving a region and NSView isn't set up for that to happen.
-  scoped_nsobject<ToolTip> tooltip_;
 
   // Factory used to safely scope delayed calls to ShutdownHost().
   ScopedRunnableMethodFactory<RenderWidgetHostViewMac> shutdown_factory_;
 
   // Used for positioning a popup menu.
   BaseView* parent_view_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_