From fc6bed0372e51c3dd7c7f0cbb4b848dae426f5f2 Mon Sep 17 00:00:00 2001
From: Justin Lebar <justin.lebar@gmail.com>
Date: Wed, 5 Sep 2012 10:34:06 -0400
Subject: [PATCH] Bug 787378 - Part 1: Fire a "firstpaint" event in iframe
 mozbrowser.

---
 dom/browser-element/BrowserElementChild.js  | 19 +++++++++++++++++++
 dom/browser-element/BrowserElementParent.js |  1 +
 2 files changed, 20 insertions(+)

diff --git a/dom/browser-element/BrowserElementChild.js b/dom/browser-element/BrowserElementChild.js
index 86e9c10c4fb..0d2d706747e 100644
--- a/dom/browser-element/BrowserElementChild.js
+++ b/dom/browser-element/BrowserElementChild.js
@@ -107,6 +107,12 @@ BrowserElementChild.prototype = {
                      /* useCapture = */ true,
                      /* wantsUntrusted = */ false);
 
+    this._afterPaintHandlerClosure = this._afterPaintHandler.bind(this);
+    addEventListener('MozAfterPaint',
+                     this._afterPaintHandlerClosure,
+                     /* useCapture = */ true,
+                     /* wantsUntrusted = */ false);
+
     var self = this;
     function addMsgListener(msg, handler) {
       addMessageListener('browser-element-api:' + msg, handler.bind(self));
@@ -351,6 +357,19 @@ BrowserElementChild.prototype = {
     }
   },
 
+  _afterPaintHandler: function(e) {
+    let uri = docShell.QueryInterface(Ci.nsIWebNavigation).currentURI;
+    debug("Got afterpaint event: " + uri.spec);
+    if (uri.spec != "about:blank") {
+      /* this._afterPaintHandlerClosure == arguments.callee, except we're in
+       * strict mode so we don't have arguments.callee. */
+      removeEventListener('MozAfterPaint', this._afterPaintHandlerClosure,
+                          /* useCapture */ true);
+
+      sendAsyncMsg('firstpaint');
+    }
+  },
+
   _closeHandler: function(e) {
     let win = e.target;
     if (win != content || e.defaultPrevented) {
diff --git a/dom/browser-element/BrowserElementParent.js b/dom/browser-element/BrowserElementParent.js
index 152520215c0..a9fca6a470c 100644
--- a/dom/browser-element/BrowserElementParent.js
+++ b/dom/browser-element/BrowserElementParent.js
@@ -195,6 +195,7 @@ function BrowserElementParent(frameLoader, hasRemoteFrame) {
   addMessageListener("securitychange", this._fireEventFromMsg);
   addMessageListener("error", this._fireEventFromMsg);
   addMessageListener("scroll", this._fireEventFromMsg);
+  addMessageListener("firstpaint", this._fireEventFromMsg);
   addMessageListener("keyevent", this._fireKeyEvent);
   addMessageListener("showmodalprompt", this._handleShowModalPrompt);
   addMessageListener('got-screenshot', this._gotDOMRequestResult);