Adding the capacity to interact with modal dialogs to the automation framework.
This change will be used by Ojan to implement some unload handler tests.

TEST=Run the ui tests.
Review URL: http://codereview.chromium.org/13113

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6402 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed