Web Animations API: Add performance tests to WebKet/PerformanceTests/Animation

Review URL: https://codereview.chromium.org/239623004

git-svn-id: svn://svn.chromium.org/blink/trunk@171758 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add support for setting password value gated on user's gesture in a page

WebViewImpl will now be able to notify WebAutofillClient when a user gesture is handled for the first time after a load.
This has security motivation, detailed here:
https://docs.google.com/document/d/1_Es0qQVrKZSZoXuQBuPmNW8-EAUDsuQGSMIlRFPzs_0/edit?usp=sharing

This improves the current status, when a workaround involving checking for a user gesture outside of Blink is used. That workaround does not work for Android, and can be seen as a layering violation in the sense, that checking for user gesture is a Blink internal thing.

There was one technical challenge to tackle in this approach: the need to know in WebViewImpl, whether a event satisfies isUserGestureEventType, because such events can get created higher up the stack, in EventRouter. For example, the GestureTap event does not satisfy isUserGestureEventType, but causes a mouse click event to be created, which satisfies isUserGestureEventType. That event is never seen by WebViewImpl. That's why this CL also needs to add a check for UserGestureIndicator being created during the handleEvent call.

This is the Blink part, two more CLs are planned as follow-ups:
1) Chromium part: PasswordAutofillAgent receiving the newly added notification + clean-up (basically getting rid of content/ changes from https://codereview.chromium.org/163843002)
2) Blink clean-up: making WebInputEvent::isUserGestureEventType Blink-internal

BUG=163072

Review URL: https://codereview.chromium.org/235983016

git-svn-id: svn://svn.chromium.org/blink/trunk@171759 bbb929c8-8fbe-4397-9dbb-9b2b20218538