Move FindPasteboard to ui/base/cocoa since it's used by two modules (content+chrome).

ui/ui.gyp

 # Copyright (c) 2012 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,
   },
   'includes': [
     'ui_resources.gypi',
@@ skipping 67 matching lines @@
         'base/clipboard/clipboard_aurax11.cc',
         'base/clipboard/clipboard_gtk.cc',
         'base/clipboard/clipboard_mac.mm',
         'base/clipboard/clipboard_util_win.cc',
         'base/clipboard/clipboard_util_win.h',
         'base/clipboard/clipboard_win.cc',
         'base/clipboard/custom_data_helper.cc',
         'base/clipboard/custom_data_helper.h',
         'base/clipboard/custom_data_helper_mac.mm',
         'base/clipboard/custom_data_helper_x.cc',
+        'base/clipboard/find_pasteboard.h',
+        'base/clipboard/find_pasteboard.mm',
         'base/clipboard/scoped_clipboard_writer.cc',
         'base/clipboard/scoped_clipboard_writer.h',
         'base/cocoa/base_view.h',
         'base/cocoa/base_view.mm',
         'base/cocoa/events_mac.mm',
         'base/cocoa/focus_tracker.h',
         'base/cocoa/focus_tracker.mm',
         'base/dragdrop/cocoa_dnd_util.h',
         'base/dragdrop/cocoa_dnd_util.mm',
         'base/dragdrop/drag_drop_types_gtk.cc',
@@ skipping 592 matching lines @@
                 'shutil.copyfile(\'<(ui_copy_target)\', \'<(ui_copy_dest)\'); ' \
                 'os.chmod(\'<(ui_copy_dest)\', 0700)'
               ]
             }
           ],
         },
       ],
     }],
   ],
 }