[Android] Don't wait for background tabs

tools/perf/measurements/session_restore.py

 # Copyright 2013 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.
 
 from measurements import startup
 from metrics import cpu
 from metrics import startup_metric
 
 
 class SessionRestore(startup.Startup):
@@ skipping 33 matching lines @@
     if len(wpr_archives.keys()) > 1:
       raise Exception("Invalid pageset: more than 1 WPR archive found.: " +
           ', '.join(wpr_archives.keys()))
 
   def DidStartBrowser(self, browser):
     self._cpu_metric = cpu.CpuMetric(browser)
     self._cpu_metric.Start(None, None)
 
   def MeasurePage(self, page, tab, results):
     # Wait for all tabs to finish loading.
-    for i in xrange(len(tab.browser.tabs)):
-      t = tab.browser.tabs[i]
+    if 'android' in tab.browser.browser_type:

[tonyg, 2014/02/12 22:25:57]

I don't like defining the metric differently by platform. I think the metric
should just be Speed Index measured from launching the browser until foreground
tab visually complete.

If that is too much to bite off immediately, then I recommend we do the proposed
android behavior for all platforms.

[aberent, 2014/02/13 11:37:43]

Switched to Android behaviour in all cases. Switching to speed index looks more
difficult, since it depends on polling the tab to decide whether there is more
data coming, and in this case we want to start timing before the tab (or Chrome)
exists. As such I am not doing that now.

+      # On android the background tabs are loaded on demand, so wont have been
+      # loaded at this stage; so only wait for the foreground tab. Also
+      # document.hidden is broken on Android - crbug.com/322544 so assume this
+      # is tab[0]
+      t = tab.browser.tabs[0]
       t.WaitForDocumentReadyStateToBeComplete()
+    else:
+      for i in xrange(len(tab.browser.tabs)):
+        t = tab.browser.tabs[i]
+        t.WaitForDocumentReadyStateToBeComplete()
 
     # Record CPU usage from browser start to when all pages have loaded.
     self._cpu_metric.Stop(None, None)
     self._cpu_metric.AddResults(tab, results, 'cpu_utilization')
 
     startup_metric.StartupMetric().AddResults(tab, results)
 
     # TODO(jeremy): Measure time to load - first, last and frontmost tab here.

[jeremy, 2014/02/13 09:40:15]

Can you leave this comment in when you make the change.

[aberent, 2014/02/13 11:37:43]

Done.