Revert 137540 - Disable off-store extension installs by default. Also get rid of ExtensionService::IsDownloadFromGallery.

BUG=55584

Review URL: https://chromiumcodereview.appspot.com/10356052

TBR=aa@chromium.org
Review URL: https://chromiumcodereview.appspot.com/10387167

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137575 0039d316-1c4b-4281-b951-d872f2087c98
19 files changed