DumpAccessibilityTreeTest.AccessibilityModalDialogInIframeClosed is occasionally failing on yakju-clang-clankium, eg:

https://chromegw.corp.google.com/i/internal.client.clank/builders/yakju-clang-clankium/builds/2561
https://chromegw.corp.google.com/i/internal.client.clank/builders/yakju-clang-clankium/builds/2562
https://chromegw.corp.google.com/i/internal.client.clank/builders/yakju-clang-clankium/builds/2565
https://chromegw.corp.google.com/i/internal.client.clank/builders/yakju-clang-clankium/builds/2571
https://chromegw.corp.google.com/i/internal.client.clank/builders/yakju-clang-clankium/builds/2574
https://chromegw.corp.google.com/i/internal.client.clank/builders/yakju-clang-clankium/builds/2579

The logs contain:

../../content/browser/accessibility/dump_accessibility_browsertest_base.cc:339: Failure
Value of: is_different
  Actual: true
Expected: false
[ERROR:dump_accessibility_browsertest_base.cc(364)] Diff:
* Line Expected
- ---- --------
     1 android.webkit.WebView focusable focused scrollable
     2 ++android.view.View
     3 ++++android.view.View clickable name='Test for modal dialog closed in an iframe. '
     4 ++++android.view.View
*    5 ++++++android.view.View focusable scrollable
     6 ++++++++android.view.View
     7 ++++++++++android.widget.Button role_description='button' clickable focusable name='I am a non-inert button!'
     8 <-- End-of-file -->

Actual
------
android.webkit.WebView focusable focused scrollable
++android.view.View
++++android.view.View clickable name='Test for modal dialog closed in an iframe. '
++++android.view.View
<-- End-of-file -->