Prevent sending click event for non primary button

Prevent sending click and dblclick events when the
button in charge is a non-primary mouse button.

As the result of this change there is no way to
prevent the behavior of opening a new tap when
middle clicking on a link. Previously, js could
listen to click event of the middle button and
call preventDefault on it.

BUG=255

Review-Url: https://codereview.chromium.org/1894253002
Cr-Commit-Position: refs/heads/master@{#390195}
6 files changed