Ensure that search engine dialog appears on top when it appears.
Ensure that search engine dialog appears on top when it appears.

BUG=54417
TEST= install chrome.  during install, click on another app. search engine dialog should appear on top.
Review URL: http://codereview.chromium.org/3350008

git-svn-id: http://src.chromium.org/svn/trunk/src@58509 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 796d3f27427dd2b2c37a4c8e4bf6e6ded27d7b63
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