Fix the T-Rex easter egg on iOS.

components/neterror/resources/offline.js

Index: components/neterror/resources/offline.js
diff --git a/components/neterror/resources/offline.js b/components/neterror/resources/offline.js
index 005f4f3ae20dc570369df092d783a9e5bfec0e13..391a512aefa6e89b3045a3064eb3e55a027009cb 100644
--- a/components/neterror/resources/offline.js
+++ b/components/neterror/resources/offline.js
@@ -292,7 +292,16 @@ Runner.prototype = {
       this.spriteDef = Runner.spriteDefinition.LDPI;
     }
 
-    this.init();
+    if (!Runner.imageSprite.complete) {

[edwardjung, 2016/07/18 10:37:11]

Do a positive check for the 'complete' property.

if (Runner.imageSprite.complete) {
   …  
} else {
   …
}

[kkhorimoto, 2016/07/20 01:18:29]

Done.

+      // If the images are not yet loaded, add a listener.
+      Runner.imageSprite.runner = this;
+
+      Runner.imageSprite.onload = function() {
+        this.runner.init();
+      }

[edwardjung, 2016/07/18 10:37:11]

I would use the addEventListener style of attaching a listener that is used
everywhere else. Cleaner and you can bind 'this' to the function at the same
time:

Runner.imageSprite.addEventListener(Runner.events.LOAD, this.init.bind(this));

[kkhorimoto, 2016/07/20 01:18:29]

Done.

+    } else {
+      this.init();
+    }
   },
 
   /**
@@ -660,7 +669,9 @@ Runner.prototype = {
         if (!this.activated) {
           this.loadSounds();
           this.activated = true;
-          errorPageController.trackEasterEgg();
+          if (errorPageController) {
+            errorPageController.trackEasterEgg();
+          }

[edwardjung, 2016/07/18 10:37:11]

Will there ever be an instance where errorPageController won't exist at this
point? We always want to track the easter egg activations.

Regardless, the check should be:

if (window.errorPageController) {
 …
}

As otherwise this would throw a reference error if errorPageController doesn't
exist.

[kkhorimoto, 2016/07/20 01:18:29]

errorPageController is consistently nil on iOS.  Somehow my previous check of
"if (errorPageController)" wasn't throwing an exception when I uploaded this
first patch, but now it does, so the "window" portion is added.  I can't seem to
find where this variable is set though; from your comment it seems like it is
probably a bug that it is nil here.

[edwardjung, 2016/07/20 21:37:57]

errorPageController is exposed from NetErrorPageController::Install() as a
global so it should exist. 
https://cs.chromium.org/chromium/src/chrome/renderer/net/net_error_page_contr...

This used to work without this check, so I'm wondering if something changed in
the transition to WKWebView? 

         }
 
         if (!this.tRex.jumping && !this.tRex.ducking) {