Enable input-mode by default.

Approved Intent to Ship:
https://groups.google.com/a/chromium.org/d/msg/blink-dev/MAHQkH4vvUQ/i0yCobrMCQAJ

BUG=244688

Change-Id: I76f996b728bac093033f6e12d239cb3819616a91
Reviewed-on: https://chromium-review.googlesource.com/919201
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Rick Byers <rbyers@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537210}
3 files changed