Telemetry: Fix inbox_app.html?slide_drawer of key_silk_cases.

tools/perf/page_sets/key_silk_cases.py

 # Copyright 2014 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 telemetry.page import page as page_module
 from telemetry.page import page_set as page_set_module
 
 
 class KeySilkCasesPage(page_module.Page):
 
   def __init__(self, url, page_set):
@@ skipping 345 matching lines @@
       url='file://key_silk_cases/inbox_app.html?slide_drawer',
       page_set=page_set)
 
   def ToggleDrawer(self, action_runner):
     interaction = action_runner.BeginGestureInteraction(
         'TapAction', is_smooth=True)
     action_runner.TapElement('#menu-button')
     interaction.End()
 
     interaction = action_runner.BeginInteraction('Wait', is_smooth=True)
-    action_runner.WaitForJavaScriptCondition(
-        'document.getElementById("nav-drawer").active')
+    action_runner.WaitForJavaScriptCondition('''
+        document.getElementById("nav-drawer").active &&
+        document.getElementById("nav-drawer").children[0]
+            .getBoundingClientRect().left == 0''')
     interaction.End()
 
   def RunNavigateSteps(self, action_runner):
     action_runner.NavigateToPage(self)
     action_runner.Wait(2)
     self.ToggleDrawer(action_runner)
 
   def RunSmoothness(self, action_runner):
     self.SlideDrawer(action_runner)
 
@@ skipping 268 matching lines @@
     self.AddPage(Page19(self))
     self.AddPage(Page20(self))
     self.AddPage(Page21(self))
     self.AddPage(Page22(self))
     self.AddPage(Page23(self))
     self.AddPage(Page24(self))
     self.AddPage(Page25(self))
     self.AddPage(Page26(self))
     self.AddPage(SVGIconRaster(self))
     self.AddPage(UpdateHistoryState(self))