Originally nsImageFrame uses InvalidateLayer() to update the image. For layers-free, we need an alternative way to do this. [1] https://dxr.mozilla.org/mozilla-central/source/layout/generic/nsImageFrame.cpp?q=nsImageFrame.cpp&redirect_type=direct#644

Comment on attachment 8889292 [details] Bug 1382985 - Support image animation for layers-free mode. https://reviewboard.mozilla.org/r/160342/#review166236 ::: layout/generic/nsImageFrame.cpp:645 (Diff revision 2) > > void > nsImageFrame::InvalidateSelf(const nsIntRect* aLayerInvalidRect, > const nsRect* aFrameInvalidRect) > { > + if (gfxPrefs::WebRenderLayersFree() && HasProperty(nsIFrame::WebRenderUserDataProperty())) { I would get rid of the gfxPrefs check here. The HasProperty check should be sufficient - that will only exist if we're in layers free mode. I don't like having the check because if we change the conditions for layers-free then we'd have to update it in multiple places. ::: layout/generic/nsImageFrame.cpp:653 (Diff revision 2) > + RefPtr<WebRenderUserData> data; > + userDataTable->Get(nsDisplayItem::TYPE_IMAGE, getter_AddRefs(data)); > + if (data && data->AsFallbackData()) { > + data->AsFallbackData()->SetInvalid(true); > + } > + SchedulePaint(PAINT_DEFAULT); Don't need to specify PAINT_DEFAULT here since it's the default value of this arg anyway.

try result: https://treeherder.mozilla.org/#/jobs?repo=try&revision=a9df38a4888e9191dc4342d2e4b7b9ea1a558e63

Pushed by ethlin@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/d2513137446a Support image animation for layers-free mode. r=kats