GitLab

Adds an UnhandledKeyboardEventHandler member to the BubbleWebView
to allow the WebView and embedder to deal with key events that
were not handled by the WebContents.

Sets allow_accelerators_ to true to ensure that embedders of the
BubbleWebView are able to capture and respond to accelerators.

Bug: 1138967
Change-Id: Ib629de2dbb0f1b6e41f4116fcff6d1413fc3061c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2496504Reviewed-by: Peter Boström <pbos@chromium.org>
Commit-Queue: Thomas Lukaszewicz <tluk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821040}