Added five Popup Blocker tests.
Added five Popup Blocker tests.

 - testMultiplePopups - verify that multiple popups are blocked.
 - testPopupBlockedEverySec - Verify that popups launched are blocked every second.
 - testPopupsLaunchWhenBrowserBackButton - Verify that popups are launched when the browser back button is pressed.
 - testBlockPopupsFromExternalSite - Verify popups are blocked from an external site.
 - testPopupsLaunchWhenTabIsClosed - Verify that popups are launched when leaving a page.

TEST=none
BUG=none
Review URL: http://codereview.chromium.org/6820006

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@81153 0039d316-1c4b-4281-b951-d872f2087c98

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