GitLab

Devtools was not correctly handling input that is not generated by itself
and invoking callbacks when the input wasn't actually processed.

Add a modifier indicating content was injected using the debugger so that
we can then query for that to determine if we should release the event.
This is a stop gap solution until we can actually bind callbacks into the
sending of events and devtools wouldn't need its own queues of callbacks.

BUG=789869

Change-Id: I2b56e8ebf4921b48bd4d35dee2226d7cb780cb94
Reviewed-on: https://chromium-review.googlesource.com/804357
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521454}