introduce chrome/browser/common directory and move url_database(and its dependencies)

WATCHLISTS

 # 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.
 
 # Watchlist Rules
 # Refer: http://dev.chromium.org/developers/contributing-code/watchlists
 
 # IMPORTANT: The regular expression filepath is tested against each path using
 # re.search, so it is not usually necessary to add .*.
 
@@ skipping 50 matching lines @@
     'base_memory': {
       'filepath': '^base/memory',
     },
     'browser': {
       'filepath': 'chrome/browser/',
     },
     'browser_chromeos': {
       'filepath': 'chrome/browser/chromeos/',
     },
     'browser_components': {
-      'filepath': 'chrome/browser/autofill/|'\
-        'chrome/browser/history/|'\
-        'chrome/browser/bookmarks/|'\
-        'chrome/browser/favicon/',
+      'filepath': 'chrome/browser/autofill/' \
+                  '|chrome/browser/bookmarks/' \
+                  '|chrome/browser/common/' \
+                  '|chrome/browser/favicon/' \
+                  '|chrome/browser/history/'
     },
     'browser_compositor': {
       'filepath': 'ui/compositor/'
     },
     'browser_resources': {
       'filepath': 'chrome/browser/resources/',
     },
     'browsing_data': {
       'filepath': 'chrome/browser/browsing_data/',
     },
@@ skipping 487 matching lines @@
                    'groby+watch@chromium.org',
                    'rouslan+watch@chromium.org'],
     'website_settings': ['markusheintz@chromium.org'],
     'webkit': ['darin-cc@chromium.org'],
     'worker': ['jam@chromium.org'],
     'x11': ['derat+watch@chromium.org',
             'sadrul@chromium.org',
             'yusukes+watch@chromium.org'],
   },
 }