Browser plugin: Implement titleChanged event.

content/test/data/browser_plugin_embedder_titlechange.html

Index: content/test/data/browser_plugin_embedder_titlechange.html
diff --git a/content/test/data/browser_plugin_embedder_titlechange.html b/content/test/data/browser_plugin_embedder_titlechange.html
new file mode 100644
index 0000000000000000000000000000000000000000..f0f906dca402acf647e130c6e686f273fcd6e2af
--- /dev/null
+++ b/content/test/data/browser_plugin_embedder_titlechange.html
@@ -0,0 +1,24 @@
+<script type="text/javascript">
+function titleChange(evt) {
+  document.title = evt.title;
+}
+function SetSrc(src) {
+  var plugin = document.getElementById('plugin');
+  plugin.src = src;
+}
+function Back() {
+  var plugin = document.getElementById('plugin');
+  plugin.back();
+}
+</script>
+
+<object id="plugin"
+    tabindex="0"
+    type="application/browser-plugin"
+    width="640"
+    height="480"
+    border="0px"></object>
+<script type="text/javascript">
+  var plugin = document.getElementById('plugin');
+  plugin.addEventListener('titlechange', titleChange);
+</script>