Add kEditingModifier constant.

This constant represents the WebInputEvent::kMetaKey on Mac, and
WebInputEvent::kControlKey on other platforms. It can be checked against
web event modifiers to determine if the editing key (command on Mac
and control on other platforms) is held down.

BUG=59266

Change-Id: Ibdc67e56441fbf3855169fbf6ca1101884d86f38
Reviewed-on: https://chromium-review.googlesource.com/583855
Commit-Queue: Diana Gage <drgage@google.com>
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#489464}
1 file changed