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

chrome/chrome.gyp

 # Copyright (c) 2009 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.
 
 {
   'variables': {
     'chromium_code': 1,
     # Define the common dependencies that contain all the actual
     # Chromium functionality.  This list gets pulled in below by
     # the link of the actual chrome (or chromium) executable on
@@ skipping 1835 matching lines @@
             '../third_party/GTM/AppKit/GTMNSBezierPath+RoundRect.m',
             '../third_party/GTM/AppKit/GTMNSColor+Luminance.m',
             '../third_party/GTM/AppKit/GTMTheme.m',
             '../third_party/GTM/AppKit/GTMUILocalizer.h',
             '../third_party/GTM/AppKit/GTMUILocalizer.m',
             # Build necessary Mozilla sources
             '../third_party/mozilla/include/NSScreen+Utils.h',
             '../third_party/mozilla/include/NSScreen+Utils.m',
             '../third_party/mozilla/include/NSWorkspace+Utils.h',
             '../third_party/mozilla/include/NSWorkspace+Utils.m',
-            '../third_party/mozilla/include/ToolTip.h',
-            '../third_party/mozilla/include/ToolTip.mm',
           ],
           'include_dirs': [
             '../third_party/GTM',
             '../third_party/GTM/AppKit',
           ],
           'link_settings': {
             'libraries': [
               '$(SDKROOT)/System/Library/Frameworks/SecurityInterface.framework',
               '$(SDKROOT)/System/Library/Frameworks/QuartzCore.framework',
             ],
@@ skipping 3005 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],
   ],  # 'conditions'
 }