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

chrome/chrome_tests.gypi

Index: chrome/chrome_tests.gypi
===================================================================
--- chrome/chrome_tests.gypi	(revision 157579)
+++ chrome/chrome_tests.gypi	(working copy)
@@ -184,8 +184,8 @@
         'browser/ui/gtk/test/ui_test_utils_gtk.cc',
         'browser/ui/panels/base_panel_browser_test.cc',
         'browser/ui/panels/base_panel_browser_test.h',
-	'browser/ui/panels/test_panel_notification_observer.cc',
-	'browser/ui/panels/test_panel_notification_observer.h',
+        'browser/ui/panels/test_panel_notification_observer.cc',
+        'browser/ui/panels/test_panel_notification_observer.h',
         'browser/ui/panels/test_panel_active_state_observer.cc',
         'browser/ui/panels/test_panel_active_state_observer.h',
         'browser/ui/panels/test_panel_mouse_watcher.cc',
@@ -1192,6 +1192,7 @@
         'browser/chromeos/version_loader_unittest.cc',
         'browser/chromeos/web_socket_proxy_helper_unittest.cc',
         'browser/command_updater_unittest.cc',
+        'browser/common/url_database/url_database_unittest.cc',
         'browser/component_updater/test/component_installers_unittest.cc',
         'browser/component_updater/test/component_updater_service_unittest.cc',
         'browser/component_updater/component_updater_interceptor.cc',
@@ -1362,7 +1363,6 @@
         'browser/history/thumbnail_database_unittest.cc',
         'browser/history/top_sites_database_unittest.cc',
         'browser/history/top_sites_unittest.cc',
-        'browser/history/url_database_unittest.cc',
         'browser/history/visit_database_unittest.cc',
         'browser/history/visit_filter_unittest.cc',
         'browser/history/visit_tracker_unittest.cc',