about:net-internals#prerender: Add information about load state of prerender

chrome/test/data/webui/net_internals/prerender_view.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.
 
 // Include test fixture.
 GEN_INCLUDE(['net_internals_test.js']);
 
 // Anonymous namespace
 (function() {
 
@@ skipping 80 matching lines @@
 
     // Check number of rows in both tables.
     NetInternalsTest.checkTbodyRows(PrerenderView.HISTORY_TABLE_ID,
                                     prerenderInfo.history.length);
     NetInternalsTest.checkTbodyRows(PrerenderView.ACTIVE_TABLE_ID,
                                     prerenderInfo.active.length);
 
     if (this.state_ == STATE.START_PRERENDERING) {
       this.startPrerendering_(prerenderInfo);
     } else if (this.state_ == STATE.NEED_NAVIGATE) {
+      // Can't safely swap in a prerender until the main frame has committed.
+      // Waiting until the load has completed isn't necessary, but it's simpler.
+      if (!prerenderInfo.active[0].is_loaded)

[eroman, 2013/05/29 16:45:38]

is it a given that active[0] exists?

[mmenke, 2013/05/29 17:11:28]

Yes.

The first call to this function is when there are no prerender at all.  At this
point we're at the STATE.START_PRERENDERING state.

Then we're only called on update.  The only way we could be updated is if an
entry is added to active, added to history, or moves from active to history. 
There's only one prerender request in all these tests.  If we expect it to fail
(And thus go to history), we skip this state.

So we expect the prerender to succeed, so we'll have to see it as active (Since
we haven't visited it yet, it shouldn't be added to the history - if it is, the
test will fail at another step, anyways).

+        return;
       this.navigate_(prerenderInfo);
     } else if (this.state_ == STATE.HISTORY_WAIT) {
       this.checkDone_(prerenderInfo);
     } else {
       assertNotReached();
     }
   },
 
   /**
    * Start by triggering a prerender of |url_| in a background tab.
@@ skipping 82 matching lines @@
  */
 TEST_F('NetInternalsTest', 'netInternalsPrerenderViewFail', function() {
   var taskQueue = new NetInternalsTest.TaskQueue(true);
   taskQueue.addTask(
       new NetInternalsTest.GetTestServerURLTask('files/download-test1.lib'));
   taskQueue.addTask(new PrerenderTask(false, 'Download'));
   taskQueue.run();
 });
 
 })();  // Anonymous namespace