Browser Plugin: Add HTML5-like postMessage support

content/test/data/browser_plugin_post_message_guest.html

Index: content/test/data/browser_plugin_post_message_guest.html
diff --git a/content/test/data/browser_plugin_post_message_guest.html b/content/test/data/browser_plugin_post_message_guest.html
new file mode 100644
index 0000000000000000000000000000000000000000..d28593ba8e4ea3a35494503ffb12c32ee4cf4bb9
--- /dev/null
+++ b/content/test/data/browser_plugin_post_message_guest.html
@@ -0,0 +1,10 @@
+<script>
+ window.addEventListener('message', receiveMessage, false);

[nasko, 2012/09/19 21:19:59]

nit: This makes more sense to be after the actual function.

[Fady Samuel, 2012/09/20 15:24:28]

Done.

+ function receiveMessage(event) {
+  if (event.data != 'stop') {

[nasko, 2012/09/19 21:19:59]

!==

[Fady Samuel, 2012/09/20 15:24:28]

Done.

+    event.source.postMessage('foobar', '*');
+  } else {
+    event.source.postMessage('stop_ack', '*');
+  }
+ }
+</script>