+mustaq@ who is going to draft a proposal for refactoring autoscrolling code that this would eventually take advantage of that API.

Is it actually ok to delete this code? https://codereview.chromium.org/2373123002/

FYI, we already had a long previous discussion on this.  I had uploaded similar deletion patch https://codereview.chromium.org/2255813004/ (BTW, I think it should also include zoom controller as the zoom doesn't make sense to keep existing on its own), and filed similar bug  http://crbug.com/644488 .  As before, I am OK with either deleting now, or delaying the deletion until a new C++ implementation is available to be shared among all autoscrollers.

If we go with the short-term maintenance, I think the last motion event offset could be eliminated by generating synthetic mousewheel events instead of touch events.

And on further thought, I think reopening the deletion debate at this point would mostly just be a distraction.  I was OK with the long-term maintenance plan we ended up with earlier, and I don't think this DIP problem changes the situation much.

Before we talk again about immediate deletion, please try writing a patch switching it to the synthetic mousewheel event like I mentioned above.  I think it should be pretty easy, and it would be a proof-of-concept/incremental step towards the autoscroll controller plan.

c#4: I do not immediately understand how to generate "synthetic mousewheel events instead of touch events". Alex, could you please point me to some example or docs?

It should be this kind of object or a Java/UI side event that generates that: https://cs.chromium.org/chromium/src/third_party/WebKit/public/platform/WebInputEvent.h?q=WebMouseWheelEvent&sq=package:chromium&l=404

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4537fa801ee646b95ef496083e824e468978a374

commit 4537fa801ee646b95ef496083e824e468978a374
Author: timav <timav@chromium.org>
Date: Mon Dec 12 06:46:54 2016

Emulate Android joystick scroll with synthetic mouse wheel event

The JoystickScrollProvider Java class used to emulate a View
scroll events and call ContentViewCore.scrollBy(), now it
emulates the mouse wheel events directly, dropping the calculation
of the current event position (it is set to (0,0)).

This CL also removes JoystickScrollProvider dependency on
ContentViewCore, it talks to its own native counterpart.

BUG= 620929 ,  650351 

Review-Url: https://codereview.chromium.org/2548363007
Cr-Commit-Position: refs/heads/master@{#437826}

[modify] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/browser/BUILD.gn
[modify] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/browser/android/browser_jni_registrar.cc
[add] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/browser/android/joystick_scroll_provider.cc
[add] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/browser/android/joystick_scroll_provider.h
[modify] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/public/android/BUILD.gn
[modify] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/public/android/java/src/org/chromium/content/browser/ContentView.java
[modify] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java
[modify] https://crrev.com/4537fa801ee646b95ef496083e824e468978a374/content/public/android/java/src/org/chromium/content/browser/input/JoystickScrollProvider.java

aelias@, could you take a look at this? Does this require any further work?