Fixing the flakiness of a couple of popups tests.
Fixing the flakiness of a couple of popups tests.

Enabling the test popups.PopupsTest.testPopupBlockerInIncognito

BUG=70659
TEST=popups.PopupsTest.testPopupBlockerInIncognito and popups.PopupsTest.testLaunchBlockedPopupInIncognito should pass on Linux pyauto bot
Review URL: http://codereview.chromium.org/6853002

git-svn-id: http://src.chromium.org/svn/trunk/src@81771 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 0f75191f758247f9859ea3b835d1b0cebdfadcd3
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser