Unable to reproduce the issue on Mac 10.12.3 using chrome version 56.0.2924.87  with the below steps

1.Opened the PDF https://arxiv.org/pdf/1611.02167.pdf
2.Zoomed in to 250% to get horizontal overflow
3.Try scrolling
4.Able to scroll without any issues.

Please find the attached screen cast and confirm if anything missed here in triaging the issue.

Thanks,

Deleted: 694393.mp4 2.1 MB

	694393.mp4 2.1 MB View Download

I can reproduce this. It looks like if we hit the horizontal extent we go straight into a gesture nav, rather than rubber banding until a new gesture activates the navigation.

I'm suspecting something out-of-process related here. James loves PDF scrolling issues, mind taking a look? :)

Right now rubber-banding is broken on Mac for WebView:

https://bugs.chromium.org/p/chromium/issues/detail?id=628742

I'm going to guess that's related to this bug, but I won't mark them as dups just yet.

I can also reproduce this on chrome os with both the touchscreen and trackpad.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bf5beebbd5dea348bda215061cea04289d86e9f1

commit bf5beebbd5dea348bda215061cea04289d86e9f1
Author: mcnee <mcnee@chromium.org>
Date: Mon May 15 16:47:20 2017

Don't drop mouse wheel events with phase ending information in RWHVCF.

Currently, RenderWidgetHostViewChildFrame::ProcessMouseWheelEvent drops
mouse wheel events that have deltas of 0. However, we may see mouse
wheel events carrying phase ending information that have deltas of 0.
When these are dropped, MouseWheelEventQueue is not informed that
the user's gesture has ended. So when it sees subsequent wheel events,
it considers them all part of the same gesture.

By allowing events with phase ending information through,
MouseWheelEventQueue is able to properly start and end gesture scrolls.

BUG= 694393 ,  628742 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2866523002
Cr-Commit-Position: refs/heads/master@{#471797}

[modify] https://crrev.com/bf5beebbd5dea348bda215061cea04289d86e9f1/content/browser/frame_host/render_widget_host_view_child_frame.cc
[modify] https://crrev.com/bf5beebbd5dea348bda215061cea04289d86e9f1/content/browser/site_per_process_mac_browsertest.mm

OverscrollController does not do gesture-nav if the scroll-begin event is consumed, right? And events that go to the plugin are marked as consumed, as far as I remember. So can you explain why we get the gesture-nav in the reported cases? (i.e. the stream of events that OverscrollController sees that triggers the gesture-nav?)

Gesture/touch events go directly to the guest, and not to the plugin in the embedder.

OverscrollController is looking for consumed GestureScrollUpdates to prevent the gesture-nav: https://cs.chromium.org/chromium/src/content/browser/renderer_host/overscroll_controller.cc?l=157

Consumed GestureScrollUpdates in the guest are not resent to the embedder, so OverscrollController doesn't see them. Once the guest stops consuming GestureScrollUpdates, it will start resending the unconsumed GestureScrollUpdates, which the OverscrollController will see.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb

commit 19fd249f2bd7f2a7ebf6f26a365119ac71e694cb
Author: mcnee <mcnee@chromium.org>
Date: Thu Jun 01 14:42:43 2017

Notify OverscrollController of gesture events in plugins.

RenderWidgetHostViewGuest resends unconsumed GestureScrollUpdates to
its embedder (via BrowserPluginGuest::ResendEventToEmbedder) which
are then individually wrapped by RenderWidgetHostImpl with
GestureScrollBegins and GestureScrollEnds. Hence OverscrollController
(a) sees a GestureScrollEnd immediately following every
GestureScrollUpdate and ends the overscroll gesture, and (b) does not
see GestureScrollUpdates consumed by the plugin, so
OverscrollController starts an overscroll gesture even though the
content of the plugin was scrolled. Also, OverscrollController does
not have a chance to filter the plugin's gesture events, so even if
an overscroll gesture has started, the plugin can start consuming
scroll updates again.

We now notify OverscrollController (as well as the Mac history
swiper) of the ACKed gesture events from the plugin, so that it
can update its state correctly and allow it to filter the gesture
events of the plugin. They also ignore the wrapper
GestureScrollBegins and GestureScrollEnds as they do not indicate
the beginning/end of the user's gesture.

Note that OOPIF-based guests do not use this resending logic. They
instead rely on RenderWidgetHostViewChildFrame's scroll bubbling
logic. Ensuring this is correct w.r.t. overscroll is being tracked
in  crbug.com/713368  .

BUG= 694393 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2815823003
Cr-Commit-Position: refs/heads/master@{#476282}

[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/chrome/browser/apps/guest_view/web_view_browsertest.cc
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_history_swiper.mm
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/frame_host/render_widget_host_view_child_frame.cc
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/frame_host/render_widget_host_view_child_frame.h
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/frame_host/render_widget_host_view_guest.cc
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/frame_host/render_widget_host_view_guest.h
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/renderer_host/overscroll_controller.cc
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/renderer_host/overscroll_controller.h
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/renderer_host/render_widget_host_view_aura.cc
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/renderer_host/render_widget_host_view_aura.h
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/renderer_host/render_widget_host_view_base.cc
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/browser/renderer_host/render_widget_host_view_base.h
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/public/test/browser_test_utils.cc
[modify] https://crrev.com/19fd249f2bd7f2a7ebf6f26a365119ac71e694cb/content/public/test/browser_test_utils.h