Unable to reproduce the issue on Windows 7, Ubuntu 14.04 using 51.0.2704.79, latest stable 51.0.2704.84, canary 53.0.2764.0 as per above steps.

Please find attached screencast.

jidanni@Could you please check the issue on clean profile and update the thread with screencast if issue still persists.

Deleted: 618859.mp4 2.9 MB

	618859.mp4 2.9 MB View Download

All I know is one will miss about three lines per page.
Your video is too fast for me, but I trust things work fine on your computer.
Maybe there is a font size thing going on.
Anyway, yes, tested on a totally virgin account.

Deleted: Page_1.jpg 136 KB

	Page_1.jpg 136 KB View Download

Deleted: Page_2.jpg 156 KB

	Page_2.jpg 156 KB View Download

Here on Debian one does notice:

[28962:28962:0612/020641:ERROR:master_preferences.cc(200)] Failed to read preferences from /usr/share/chromium
libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: i965
[29020:29020:0612/020642:ERROR:sandbox_linux.cc(334)] InitializeSandbox() called with multiple threads in process gpu-process
[4:4:0612/020659:ERROR:PlatformKeyboardEvent.cpp(117)] Not implemented reached in static blink::PlatformEvent::Modifiers blink::PlatformKeyboardEvent::getCurrentModifierState()
...

Thank you for providing more feedback. Adding requester "ssamanoori@chromium.org" for another review and adding "Needs-Review" label for tracking.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

I tried it on a different sized computer/screen. Same problem. I bet it has something to do with those bars across the top of the screen. Maybe they are assumed transparent.

Anyways on my different sized monitor, the first SPACEBAR down worked OK, the ant's eyes were chopped seemingly correctly. But when we get down to the text, you will notice that we miss a line or two each SPACEBAR/Page Down... we have to scroll back up to see the missing words.

Unable to reproduce the issue on Ubuntu 14.04 using latest canary 53.0.2768.0 as per steps in comment #0.

Can you believe I can even reproduce the problem here in the public library today. using:

版本 51.0.2704.84 m
 
Google Chrome 目前是最新版本。

The key is: you won't see the problem when you initially open the browser
in its 'occupy the entire window' state.

You must first click the overlapping rectangle icon in the upper right, to make (Chrome, not Chromium today) only occupy the center portion of the screen.

Now hitting a few Page Downs, you will notice that you miss about one line each time, and need to scroll back up a little for the sentences to make sense.

After you click the overlapping rectangles icon, it becomes a single rectangle icon, afterwhich you can test for the bug.

I saw similar results on http://www.popmatters.com/post/rats-writing-and-the-nature-of-evil-a-night-with-stephen-king/ running CrOS 51.0.2704.79

Seems that hitting the spacebar pages down by the entire page height, even though the text being scrolled lives below the top header. Thus you miss the height of the top header every time you scroll.

Top header is position:fixed.

Yes I see the exact problem too mentioned in comment#9 !
(P.S., I even got an aw-snap when replying to this bug, so had to use Firefox to type this. In fact that's why I haven't bothered with chromium for weeks. An aw-snap a minute.)

Yes this is exactly as #9 describes it. The page has a position fixed element and it is on top of content that is scrolled into view. The position adjusted is always the size of the browser window not just what is visible text minus the banner. It is impossible for us to determine that something is overtop of other text in this case.

It is just a poorly designed webpage for keyboard interaction. How much we scroll per page press is slightly different than FireFox and that is why it appears to work in FireFox and not Chrome. Unfortunately it is relatively easy to design that breaks in both. Just increase the size of the banner by a bit more and it will fail in FireFox as well.