Notify WebSocket connection failure, chromium side

In order to set |wasClean| property of CloseEvent and show the failure message
correctly, The blink-side WebSocket need to know whether the connection
is dropped because of a server request.

Blink side change is: https://codereview.chromium.org/36033003/
BUG=310405

Review URL: https://codereview.chromium.org/34753008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232921 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232921
Explicitly reject storage access if requesting security origin is unique

This is a follow-up fix for https://codereview.chromium.org/46583005/
(Send Allow{Database,FileSystem,IndexedDB} sync IPCs
directly from worker threads)

I needed to default behavior to allow storage access when NULL proxy
is returned to make content_shell work, and therefore needed not to
return NULL when origin.isUnique()==true case.

BUG=none
R=jam,michaeln
TBR=jam

Review URL: https://codereview.chromium.org/55433006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232922 0039d316-1c4b-4281-b951-d872f2087c98
Add a test for <dialog> in the accessibility tree

This is a test for the Blink change:
https://codereview.chromium.org/54373013/

BUG=264959

Review URL: https://codereview.chromium.org/55763002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232923 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232923