GitLab

This is a reland of be51aadb

Original change's description:
> Consistent touchpad pinch behaviour for app windows and webviews
> 
> Currently, app windows (possibly containing webviews):
> 1) suppress all pinch events which also suppresses the
>    synthetic wheel event, but not touchscreen touch events, and
> 2) allow "smart zoom" on Mac which can change the page scale even
>    though other means of changing the page scale are suppressed.
> 
> As a result of (1), if we have, say, google maps in a webview, a
> user can pinch zoom with a touchscreen, but not with a touchpad.
> 
> We now suppress gesture events to app windows based on whether they
> cause a scale change. So now touchscreen and touchpad pinching are
> consistent since the page has access to the events so that it may
> implement custom pinch zoom behaviour, but unhandled events still
> do not result in a scale change for the app window. Also, smart
> zoom is suppressed to be consistent with other touchpad pinching.
> 
> Bug: 725970, 874132
> Change-Id: I03dd2048002d69dc7c8a822fc727140c67d64706
> Reviewed-on: https://chromium-review.googlesource.com/1174933
> Reviewed-by: Ben Wells <benwells@chromium.org>
> Reviewed-by: James MacLean <wjmaclean@chromium.org>
> Reviewed-by: Ehsan Karamad <ekaramad@chromium.org>
> Commit-Queue: Kevin McNee <mcnee@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#585489}

Bug: 725970, 874132
Change-Id: I23420821c1166f7b641faf672798ddac0e928ad9
Reviewed-on: https://chromium-review.googlesource.com/1187345Reviewed-by: Ehsan Karamad <ekaramad@chromium.org>
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Reviewed-by: Ben Wells <benwells@chromium.org>
Commit-Queue: Kevin McNee <mcnee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585856}