https://cs.chromium.org/chromium/src/content/browser/renderer_host/render_widget_host_view_mac.mm?dr&sq=package:chromium&q=render_widget_host_view_mac.mm&g=0&l=204

This looks related. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/df9f8d87abe15ed4d2e96f07565bc7202c5831f3

commit df9f8d87abe15ed4d2e96f07565bc7202c5831f3
Author: Jonathan Ross <jonross@chromium.org>
Date: Thu Nov 29 21:47:25 2018

Reduce DelegatedFrameHost NOTIMPLEMENTED Calls

RenderWidgetHostViewMac explicitly sets NeedsBeginFrames upon startup.
This was setup to address some race condition.

However this is not handled by the browser process when Viz Display
Compositor is enabled. DelegatedFrameHost is spamming debug logs with
NOTIMPLEMENTED messages as a result.

All other paths to this is already checking the Viz status and not
calling in. Once Viz has launched we'll remove this legacy path.

This change updates RenderWidgetHostViewMac to not explicitly set
NeedsBeginFrames upon startup when Viz Display Compositor is
enabled.

Bug:  907246 
Change-Id: I9a584c4bedcdb1da897f8155eb151ff63ef3c8b2
Reviewed-on: https://chromium-review.googlesource.com/c/1355479
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612386}
[modify] https://crrev.com/df9f8d87abe15ed4d2e96f07565bc7202c5831f3/content/browser/renderer_host/render_widget_host_view_mac.mm