I already looked into this before. The problem is that computeVerticalScroll() guesses how much you've scrolled by using (the currently visible RecyclerView items' average height) * (number of times in the adapter) as the height of the RecyclerVirw. In our case, since the first RecyclerView element is so huge, it throws off the calculation and cuases that jump in animation when computeVerticalScroll recalculates its estimate. 

(BTW,I really thought I already filed a tracking bug for this. I'll look for it when I get back)

These is another issues, when in landscape mode, the text 'Search or type URL' is displayed, scrolling slowly, the text fades out - and then fades back in again from the side which is strange. I feel the text should not fade at all if it comes back. The alignment of the box is also about 2px out at one stage when scrolling up.

When the discard snippets cl lands - the search box scroll does not update so need to look at this too

Thanks Nicole. I'm in Australia today, so please feel free to ping me your Tuesday AM if you need input. It sounds like you're continuing to move forward and will grab me when you want eyes on this. :)

Re: Comment #1 - after looking at the video, it looks like the other bug I'm referencing (crbug/596420) is different. The other bug specifically refers to the jump the omnibox does when transitioning from above the fold to snippets.

There are a number of issues with the scroll and a bug raise for each. The initial bug intention has been fix, here are the follow up bugs:

Snapping to top or bottom: crbug/596416
Omnibox below the fold: crbug/596420
Mobile fake omnibox text fading and replacing with actual omnibox: crbug/600748

Learning tricks:
Snapping to top or bottom:  issue 596416 
Omnibox below the fold:  issue 596420 
Mobile fake omnibox text fading and replacing with actual omnibox:  issue 600748 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8d5819b2a90fc9b10fac1a2713a3f74bcfb82e29

commit 8d5819b2a90fc9b10fac1a2713a3f74bcfb82e29
Author: mcwilliams <mcwilliams@chromium.org>
Date: Fri Apr 08 16:12:23 2016

Fix the vertical scroll animation on the new tab page when scrolling up

Videos:
https://drive.google.com/corp/drive/u/0/folders/0B1IgAIJ9cgizemNwMGgzN1V1ckE

BUG= 599888 

Review URL: https://codereview.chromium.org/1872743002

Cr-Commit-Position: refs/heads/master@{#386093}

[modify] https://crrev.com/8d5819b2a90fc9b10fac1a2713a3f74bcfb82e29/chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java