Re-enable prerender RemovingLink browser tests.

chrome/test/data/prerender/prerender_events_common.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Common js for prerender loaders; defines the helper functions that put
 // event handlers on prerenders and track the events for browser tests.
 
 // TODO(gavinp): Put more common loader logic in here.
 
 // Currently only errors with the ordering of Prerender events are caught.
 var hadPrerenderEventErrors = false;
 
-var receivedPrerenderStartEvents = [];
-var receivedPrerenderLoadEvents = [];
-var receivedPrerenderStopEvents = [];
+var receivedPrerenderEvents = {
+  'webkitprerenderstart': [],
+  'webkitprerenderload': [],
+  'webkitprerenderstop': [],
+}
+var prerenderEventCallbacks = [];
 
-function PrerenderStartHandler(index) {
-  if (receivedPrerenderStartEvents[index] ||
-      receivedPrerenderLoadEvents[index] ||
-      receivedPrerenderStopEvents[index]) {
-    hadPrerenderEventErrors = true;
-    return;
-  }
-  receivedPrerenderStartEvents[index] = true;
+function GetPrerenderEventCount(index, type) {
+  return receivedPrerenderEvents[type][index] || 0;
 }
 
-function PrerenderLoadHandler(index) {
-  if (!receivedPrerenderStartEvents[index] ||
-      receivedPrerenderStopEvents[index]) {
-    hadPrerenderEventErrors = true;
-    return;
+function PrerenderEventHandler(index, ev) {
+  // Check for errors.
+  if (ev.type == 'webkitprerenderstart') {
+    if (GetPrerenderEventCount(index, 'webkitprerenderstart') ||
+        GetPrerenderEventCount(index, 'webkitprerenderload') ||
+        GetPrerenderEventCount(index, 'webkitprerenderstop')) {
+      hadPrerenderEventErrors = true;
+    }
+  } else if (ev.type == 'webkitprerenderload') {
+    if (!GetPrerenderEventCount(index, 'webkitprerenderstart') ||
+        GetPrerenderEventCount(index, 'webkitprerenderstop')) {

[mmenke, 2014/02/13 16:34:33]

Can we get multiple load events?  I guess if a page does two loads?  Think it's
worth commenting on why we don't check if we already have a load event.

[davidben, 2014/02/14 01:01:13]

Done. Yeah, multiple loads are possible.

+      hadPrerenderEventErrors = true;

[mmenke, 2014/02/14 17:33:01]

Why did you delete this block?

[davidben, 2014/02/14 19:18:26]

The check for all the events other than webkitprerenderstart are identical, so I
just moved it to an else.

[mmenke, 2014/02/14 19:25:44]

Good point.

+    }
+  } else if (ev.type == 'webkitprerenderstop') {
+    if (!GetPrerenderEventCount(index, 'webkitprerenderstart') ||
+        GetPrerenderEventCount(index, 'webkitprerenderstop')) {

[mmenke, 2014/02/13 16:34:33]

Think it's worth commenting that there may or may not a load event, in this
case.

[davidben, 2014/02/14 01:01:13]

Done.

+      hadPrerenderEventErrors = true;
+    }
   }
-  if (!receivedPrerenderLoadEvents[index])
-    receivedPrerenderLoadEvents[index] = 0;
-  receivedPrerenderLoadEvents[index]++;
+
+  // Update count.
+  receivedPrerenderEvents[ev.type][index] =
+    (receivedPrerenderEvents[ev.type][index] || 0) + 1;

[mmenke, 2014/02/13 16:34:33]

nit:  +2 indent.

[davidben, 2014/02/14 01:01:13]

Done.

+
+  // Run all callbacks. Remove the ones that are done.

[mmenke, 2014/02/13 16:34:33]

There's no documentation of how these callbacks should indicate that they're
done, that I can see.

[davidben, 2014/02/14 01:01:13]

Done.

+  prerenderEventCallbacks = prerenderEventCallbacks.filter(function(cb) {

[mmenke, 2014/02/13 16:34:33]

nit:  "cb" is more often writen out.

[davidben, 2014/02/14 01:01:13]

Done.

+    return !cb();
+  });
 }
 
-function PrerenderStopHandler(index) {
-  if (!receivedPrerenderStartEvents[index] ||
-      receivedPrerenderStopEvents[index]) {
-    hadPrerenderEventErrors = true;
-    return;
-  }
-  receivedPrerenderStopEvents[index] = true;
+// Calls |callback| when at least |count| instances of event |type| have been
+// observed for prerender |index|.
+function WaitForPrerenderEventCount(index, type, count, callback) {
+  var checkCount = function() {
+    if (GetPrerenderEventCount(index, type) >= count) {
+      callback();
+      return true;
+    }
+    return false;
+  };
+  if (!checkCount())
+    prerenderEventCallbacks.push(checkCount);
 }
 
 function AddEventHandlersToLinkElement(link, index) {
   link.addEventListener('webkitprerenderstart',
-                        PrerenderStartHandler.bind(null, index), false);
+                        PrerenderEventHandler.bind(null, index), false);
   link.addEventListener('webkitprerenderload',
-                        PrerenderLoadHandler.bind(null, index), false);
+                        PrerenderEventHandler.bind(null, index), false);
   link.addEventListener('webkitprerenderstop',
-                        PrerenderStopHandler.bind(null, index), false);
+                        PrerenderEventHandler.bind(null, index), false);
 }
 
 function AddPrerender(url, index) {
   var link = document.createElement('link');
+  link.id = 'prerenderElement' + index;
   link.rel = 'prerender';
   link.href = url;
   AddEventHandlersToLinkElement(link, index);
   document.body.appendChild(link);
   return link;
 }
 
+function RemoveLinkElement(index) {
+  var link = document.getElementById('prerenderElement' + index);
+  link.parentElement.removeChild(link);
+}
+
+function ExtractGetParameterBadlyAndInsecurely(param, defaultValue) {
+  var re = RegExp('[&?]' + param + '=([^&?#]*)');
+  var result = re.exec(document.location);
+  if (result)
+    return result[1];
+  return defaultValue;
+}
+
 function AddAnchor(href, target) {
   var a = document.createElement('a');
   a.href = href;
   if (target)
     a.target = target;
   document.body.appendChild(a);
   return a;
 }
 
 function Click(url) {
@@ skipping 74 matching lines @@
     cancelable: true,
     detail: 1,
     metaKey: true,
     shiftKey: true
   }));
 }
 
 function WindowOpen(url) {
   window.open(url);
 }