Docserver: Quick hack to stop the docserver from crashing due to the new
"commands" entry in _manifest_features.json: if multiple features are seen,
take the union of their extension_types.

BUG=316194
R=rockot@chromium.org

Review URL: https://codereview.chromium.org/65433002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233693 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 233693
When a user clicks the "accidental search" infobar link, add a shortcut for that
URL, delete the shortcut for the original search, and remove the search term
from the local search history (so the search provider also won't re-suggest
this).  This doesn't also remove the search navigation itself from history; that
didn't seem necessary, and I worried that it wouldn't be "correct" since the
user really did navigate there, if inadvertently.

This also renamed ShortcutsBackend::OnOmniboxNavigation() to the better
AddOrUpdateShortcut().

BUG=151044
TEST=Search for a previously-non-navigated intranet hostname, click the infobar link to navigate to the host, then start retyping the hostname and verify the omnibox doesn't give suggestions to re-search.
R=bartn@chromium.org

Review URL: https://codereview.chromium.org/51163003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233694 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 233694