Make initial focus consistent in all instances of cr-drawer.

This removes focus ring from "Chrome history" and "Extensions" when
showing cr-drawer using keyboard.

BUG=NONE
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2732003003
Cr-Commit-Position: refs/heads/master@{#482044}
5 files changed