[Android WebView] API to enable fullscreen.

android_webview/test/shell/assets/full_screen_video_test.html

Index: android_webview/test/shell/assets/full_screen_video_test.html
diff --git a/android_webview/test/shell/assets/full_screen_video_test.html b/android_webview/test/shell/assets/full_screen_video_test.html
index 618b3426ae08f2de9b2b99e885466d580332c795..d36c546abaf0719c7e7bef3130bcbe959a84214a 100644
--- a/android_webview/test/shell/assets/full_screen_video_test.html
+++ b/android_webview/test/shell/assets/full_screen_video_test.html
@@ -8,10 +8,13 @@ function goFullscreen(id) {
   }
 }
 
-addEventListener('Loaded', function() {
+addEventListener('DOMContentLoaded', function() {
     document.getElementById('video').addEventListener('play', function() {
         console.log('Video Played');
     }, false);
+    document.addEventListener('webkitfullscreenerror', function() {
+        javaFullScreenErrorObserver.notifyJava();
+    }, false);
 }, false);
 </script>
 </head>