[chromedriver] Add a WebView shell app for testing.

BUG=None
R=craigdh@chromium.org
TBR=navabi@chromium.org

Review URL: https://codereview.chromium.org/63373003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234255 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234255
Mojo: Add DCHECKs to entrypoints that CoreImpl has been initialized.

R=darin@chromium.org, darin

Review URL: https://codereview.chromium.org/63673003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234256 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234256