Browser: Add tips for new message received in full-screen mode

When the browser is running in full-screen mode,the status bar is
hidden,so the new message received notification can't be viewed
timely by the user.

Add a receiver to monitor the custom broadcast from MMS, and using
toast to alert users the new message received in full-screen mode.

CRs-Fixed: 534580

Change-Id: Ie3f3d6896ec30caa07303fe6e8917676e0e629a0
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 1b7fe73..fa46467 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -1076,4 +1076,6 @@
     <string name="download_path_unavailable_dlg_msg">Please modify the Download Directory of Browser</string>
     <string name="activity_not_found">Activity Not Found to Handle Intent <xliff:g id="NOACTIVITY">%s</xliff:g>.</string>
     <string name="network_switch_remind_type">wifi_browser_interaction_remind</string>
+    <!-- Toast message displayed when the full screen received message -->
+    <string name="received_message_full_screen">Receive a message from: <xliff:g id="FROM">%s</xliff:g>.</string>
 </resources>