GitLab

Adds a field trial flag to control whether to use an alternate Instant search base page URL for prefetching search results.

BUG=382694
TEST=Run chrome with the following field trial flag and observe the Instant search base page url.
     --force-fieldtrials="EmbeddedSearch/Group1 use_alternate_instant_url:1 /"

Review URL: https://codereview.chromium.org/330653004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278824 0039d316-1c4b-4281-b951-d872f2087c98