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 receivedPrerenderDomContentLoadedEvents = [];
-var receivedPrerenderStopEvents = [];
+var receivedPrerenderEvents = {
+  'webkitprerenderstart': [],
+  'webkitprerenderdomcontentloaded': [],
+  'webkitprerenderload': [],
+  'webkitprerenderstop': [],
+}
+// A list of callbacks to be called on every prerender event. Each callback
+// returns true if its condition is satisfied and false to be returned to the
+// list.

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

"condition is satisfied" is still vague - doesn't really imply will never be
called again, and "callback" doesn't imply there's some "condition" to wait for.

Suggest just "Each callback returns true if it should never be called again, or
false if not."

Alternatively, could call them prerenderConditionCheckers or some such, but that
sounds a little weird.

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

Went with the first one. prerenderConditionCheckers does sound weird.
prerenderEventConditions feels a little less wonky? shrug.

+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') {
+    // No event may preceed start.
+    if (GetPrerenderEventCount(index, 'webkitprerenderstart') ||
+        GetPrerenderEventCount(index, 'webkitprerenderdomcontentloaded') ||
+        GetPrerenderEventCount(index, 'webkitprerenderload') ||
+        GetPrerenderEventCount(index, 'webkitprerenderstop')) {
+      hadPrerenderEventErrors = true;
+    }
+  } else {
+    // There may be multiple load or domcontentloaded events, but they must not
+    // come after start and must come before stop. And there may be at most one
+    // start. Note that stop may be delivered without any load events.
+    if (!GetPrerenderEventCount(index, 'webkitprerenderstart') ||
+        GetPrerenderEventCount(index, 'webkitprerenderstop')) {
+      hadPrerenderEventErrors = true;
+    }
   }
-  if (!receivedPrerenderLoadEvents[index])
-    receivedPrerenderLoadEvents[index] = 0;
-  receivedPrerenderLoadEvents[index]++;
+
+  // Update count.
+  receivedPrerenderEvents[ev.type][index] =
+      (receivedPrerenderEvents[ev.type][index] || 0) + 1;
+
+  // Run all callbacks. Remove the ones that are done.
+  prerenderEventCallbacks = prerenderEventCallbacks.filter(function(callback) {
+    return !callback();
+  });
 }
 
-function PrerenderDomContentLoadedHandler(index) {
-  if (!receivedPrerenderStartEvents[index] ||
-      receivedPrerenderStopEvents[index]) {
-    hadPrerenderEventErrors = true;
-    return;
-  }
-  if (!receivedPrerenderDomContentLoadedEvents[index])
-    receivedPrerenderDomContentLoadedEvents[index] = 0;
-  receivedPrerenderDomContentLoadedEvents[index]++;
-}
-
-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('webkitprerenderdomcontentloaded',
+                        PrerenderEventHandler.bind(null, index), false);
   link.addEventListener('webkitprerenderload',
-                        PrerenderLoadHandler.bind(null, index), false);
-  link.addEventListener('webkitprerenderdomcontentloaded',
-                        PrerenderDomContentLoadedHandler.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);
 }