As a fix to this bug:

https://bugs.chromium.org/p/chromium/issues/detail?id=673021#c21

RenderWidgetHostViewMac sets the default needs_begin_frames_ depending on whether or
not the browser things the renderer will ever be visible:

https://cs.chromium.org/chromium/src/content/browser/renderer_host/render_widget_host_view_mac.mm?type=cs&q=renderWidgetHostViewMac&sq=package:chromium&l=438

A background page of an extension may never be visible.

However, this code is entirely Viz incompatible. The SetNeedsBeginFrame message goes directly to the Viz process and doesn't pass through the browser.

This means that Viz will regress power unless we come up with a better solution.

Pages that have content should always SetNeedsBeginFrame(true) and pages that don't should default to false. I don't know why this was a problem on Mac but this definitely needs refactoring to support Viz now.