AppRTCDemo: replace the use of query-string parameters for pre-JB devices.

Replaces the use of a query-string parameter with a (once-per-session)
JS-to-Java function call, because query-string parameters on file:// URLs are
busted on ICS and earlier Android releases
(https://code.google.com/p/android/issues/detail?id=17535).

Also added channel.html to the list of inputs to cause edits to it to cause a
rebuild of the .apk.

BUG=1949
R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1890004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4421 4adac7df-926f-26a2-2b94-8c16560cd09d

talk/examples/android/src/org/appspot/apprtc/GAEChannelClient.java

@@ -83,10 +83,11 @@ public class GAEChannelClient {
               ", desc: " + description);
         }
       });
-    proxyingMessageHandler = new ProxyingMessageHandler(activity, handler);
+    proxyingMessageHandler =
+        new ProxyingMessageHandler(activity, handler, token);
     webView.addJavascriptInterface(
         proxyingMessageHandler, "androidMessageHandler");
-    webView.loadUrl("file:///android_asset/channel.html?token=" + token);
+    webView.loadUrl("file:///android_asset/channel.html");
   }
 
   /** Close the connection to the AppEngine channel. */
@@ -106,10 +107,14 @@ public class GAEChannelClient {
     private final Activity activity;
     private final MessageHandler handler;
     private final boolean[] disconnected = { false };
+    private final String token;
 
-    public ProxyingMessageHandler(Activity activity, MessageHandler handler) {
+    public
+     ProxyingMessageHandler(Activity activity, MessageHandler handler,
+                            String token) {
       this.activity = activity;
       this.handler = handler;
+      this.token = token;
     }
 
     public void disconnect() {
@@ -120,6 +125,10 @@ public class GAEChannelClient {
       return disconnected[0];
     }
 
+    @JavascriptInterface public String getToken() {
+      return token;
+    }
+
     @JavascriptInterface public void onOpen() {
       activity.runOnUiThread(new Runnable() {
           public void run() {