Initialize is_extension_install_ properly.
Initialize is_extension_install_ properly.

BUG=32541
TEST=Start chromium a couple of times, click on downloaded PDFs and
make sure none of them are misinterpreted as an extension install.

Review URL: http://codereview.chromium.org/542114

git-svn-id: http://src.chromium.org/svn/trunk/src@36630 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: e6139c80e16ab5ae42c17f94c6432a55ca6c33ba
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