contacts: Add --enable-contacts switch.

Adds a command-line flag that results in the ContactManager
singleton being instantiated on Chrome OS (and hence, Google
contacts being periodically synced) and lists it on
chrome://flags.  Contacts aren't yet exposed in the UI.

BUG=128805
TEST=none
[email protected]

Review URL: https://chromiumcodereview.appspot.com/10880015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@153830 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 56c5dd0..43f828f 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -929,6 +929,13 @@
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kDisableWebsiteSettings),
   },
+  {
+    "enable-contacts",
+    IDS_FLAGS_ENABLE_CONTACTS_NAME,
+    IDS_FLAGS_ENABLE_CONTACTS_DESCRIPTION,
+    kOsCrOS,
+    SINGLE_VALUE_TYPE(switches::kEnableContacts)
+  },
 #if defined(USE_ASH)
   { "ash-enable-advanced-gestures",
     IDS_FLAGS_ENABLE_ADVANCED_GESTURES_NAME,