Bug 1253164 - Make nsIFrame allow running async animations once the frame is able able to run animations on the compositor again. r=birtles

For example, we don't run transform animations on large frames but once
the frame size is small enough we should run transform animations on the frame.

MozReview-Commit-ID: DkfB9g2Gcdi

--HG--
extra : rebase_source : 93a884c3063d4a6c2626e6695583664b24fe11c8

dom/animation/test/chrome/test_animation_performance_warning.html

@@ -1195,10 +1195,9 @@ function start() {
       animation.effect.target.style = 'width: 100px; height: 100px';
       return waitForFrame();
     }).then(() => {
-      // FIXME: Bug 1253164: the animation should get back on compositor.
       assert_animation_property_state_equals(
         animation.effect.getProperties(),
-        [ { property: 'transform', runningOnCompositor: false } ]);
+        [ { property: 'transform', runningOnCompositor: true } ]);
     });
   }, 'transform on too big element - area');
 
@@ -1231,10 +1230,9 @@ function start() {
       animation.effect.target.style = 'width: 100px; height: 100px';
       return waitForFrame();
     }).then(() => {
-      // FIXME: Bug 1253164: the animation should get back on compositor.
       assert_animation_property_state_equals(
         animation.effect.getProperties(),
-        [ { property: 'transform', runningOnCompositor: false } ]);
+        [ { property: 'transform', runningOnCompositor: true } ]);
     });
   }, 'transform on too big element - dimensions');
 

layout/painting/nsDisplayList.cpp

@@ -8724,6 +8724,10 @@ already_AddRefed<Layer> nsDisplayTransform::BuildLayer(nsDisplayListBuilder *aBu
     container->SetContentFlags(container->GetContentFlags() & ~Layer::CONTENT_EXTEND_3D_CONTEXT);
   }
 
+  if (mAllowAsyncAnimation) {
+    mFrame->SetProperty(nsIFrame::RefusedAsyncAnimationProperty(), false);
+  }
+
   nsDisplayListBuilder::AddAnimationsAndTransitionsToLayer(container, aBuilder,
                                                            this, mFrame,
                                                            eCSSProperty_transform);