import changes from `dev' branch of rmottola/Arctic-Fox:

- Bug 1194851. Change one instance of GetDisplayPort to HasDisplayPort. r=botond (ff16711347)
- Bug 1194851. Make ViewportHasDisplayPort only return a bool, not the displayport rect. r=botond (bfe7d49225)
- Bug 1194851. Change GetOrMaybeCreateDisplayPort into just MaybeCreateDisplayPort, and make it only return a bool, and not the displayport rect. r=botond (af2a6eedbc)
- Bug 1194851. Always store the displayport base relative to the scrollport (not the scroll frame). r=botond (841ff20d8c)
- Bug 1194851 - Remove the second parameter of IsFixedPosFrameInDisplayPort(). r=kats (7eca35088f)
- Bug 1229853 - Don't apply the displayport multiplier if we don't have a frame for the element the displayport is set on. r=tn (f0e829164e)
- Bug 1237086. When getting the displayport for a content node if there is no root scroll frame just use the primary frame of the content node. r=botond (35a1e1a2f6)
- Bug 1194851. Introduce GetDisplayPortRelativeToScrollFrame. r=botond (d209135b33)
- Bug 1194851. Change GetDisplayPortForVisibilityTesting into GetDisplayPortRelativeToScrollFrameForVisibilityTesting since it has only one user. r=botond (ba2f91af92)
- Bug 1194851. Split GetDisplayPort callers into GetDisplayPortRelative ToScrollPort and GetDisplayPortRelativeToScrollFrame. r=botond (4628829811)
- Bug 1194851. Rename GetDisplayPortRelativeToScrollPort back to GetDisplayPort. r=botond (e632511674)
- Bug 1194851. Change the GetDisplayPort API to take an optional RelativeTo parameter, instead of having that expressed in the function name. r=botond (8f0be47c51)
- Bug 1232561 part 1 - Replace AppliesToTransitionsLevel() with a cascade level enumeration; r=heycam (ca46bd9c5c)
- Bug 1229280 - Move animation generation from AnimationCollection to EffectSet; r=dbaron (7e15533b9f)
- Bug 1232561 part 2 - Move the animation style rules from AnimationCollection to EffectSet; r=heycam (6166363541)
- Bug 1232561 part 3 - Move AnimValuesStyleRule to a separate file; r=heycam (e2cc2f76c1)
- Bug 1232561 part 4 - Add EffectCompositor::ComposeAnimationRule; r=heycam (c29fef6a32)
- Bug 1232577 part 1 - Add EffectCompositor as a member of nsPresContext; r=heycam (027c5d9aa2)
- Bug 1232577 part 2 - Add a hashmap to ElementCompositor to track which (pseudo-) elements need to have their animation style rule updated; r=heycam (9d6e66d674)
- Bug 1232563 part 1 - Request a layer update if an animation is newly finished; r=heycam (9b73effbf2)
- Bug 1232563 part 2 - Move RequestRestyle calls to the effect; r=heycam (71eeb3a73d)
- Bug 1232563 part 3 - Drop check for an empty set of properties when requesting restyles from KeyframeEffectReadOnly; r=heycam (d4768a7394)
- Bug 1232563 part 4 - Don't perform style updates when the effect progress has not changed; r=heycam (8e92edd63e)
- Bug 1232577 part 3 - Move RestyleType to EffectCompositor; r=heycam (ded7dc780d)
- Bug 1232577 part 4 - Add and remove (pseudo-)elements needing an animation style rule update to the EffectCompositor; r=heycam (62f6220505)
- Bug 1232577 part 5 - Make sure CSSTransition::CancelFromStyle updates the transitions level of the cascade; r=heycam (e8912154f1)
- Bug 1232577 part 6 - Add animation rule refresh time to EffectSet; r=heycam (ba10c84ace)
- Bug 1232577 part 7 - Move call to SetNeedStyleFlush() to EffectCompositor::RequestRestyle; r=heycam (433ed32b4c)
- Bug 1232577 part 8 - Move call to PostRestyleForAnimation to EffectCompositor; r=heycam (be7dd74654)
- Bug 1232577 part 9 - Remove AnimationCollection::mStyleRuleRefreshTime; r=heycam (0fcc53cbfc)
- Bug 1232577 part 10 - Remove AnimationCollection::mStyleChanging; r=heycam (0737fe0747)
- Bug 1232577 part 11 - Remove AnimationCollection::mHasPendingAnimationRestyle; r=heycam (3d2aa0bfa4)
- Bug 1232577 part 12 - Move the remainder of RequestRestyle from AnimationCollection to EffectCompositor; r=heycam (1a180acbc2)
- Bug 1232577 part 13 - Move EnsureStyleRuleFor from AnimationCollection to EffectCompositor (dcce4b105b)
- Bug 1232577 part 14 - Move FlushAnimations to EffectCompositor; r=heycam (67e5019f44)
- Bug 1232577 part 15 - Drop LastStyleUpdateForAllAnimations flag from pres context; r=heycam (dce1abfd87)
- Bug 1232577 part 16 - Move GetAnimationRule to EffectCompositor; r=heycam (df45ee5e40)
- Bug 1232577 part 17 - Move AddStyleUpdatesTo to EffectCompositor; r=heycam (eb62d19b17)
- Bug 1232577 part 18 - Drop RestyleManager::mLastUpdateForThrottledAni…mations; r=heycam (066ca553d3)
- Bug 1232577 part 19 - Move ClearIsRunningOnCompositor to EffectCompositor; r=heycam (0bd47b0890)
- Bug 1237083 - Don't trigger layer flattening if the component alpha layer is directly on top of a forced active layer. r=roc (a54393afd9)
- Bug 1231818 - Make FrameLayerBuilder try harder to respect layers.max-active pref. r=mstange (e9cbb8d6bd)
- Bug 1231538 - Build a ContainerLayer for position:fixed and background-attachment:fixed content. r=roc (efbd221475)
- Bug 1235186 - Part 2: Fix -Wclass-varargs warning in layout/. r=dholbert (4222fbf329)
- Bug 1235186 - Part 1: Fix -Wformat warnings in layout/. r=dholbert (1f6be477be)
- Bug 1235678. Fix printing animated geometry roots of display items. r=dholbert (69dbeb290f)
- Bug 1239864 (part 9) - Use the new rect iterators in layout/ and ipc/. r=dholbert. (98626d2b36)
- Bug 1239864 (part 10) - Use the new rect iterators in view/ and widget/. r=roc. (53a86e19d6)
- Bug 1239864 (part 11) - Remove the old rect iterators. r=roc. (38d2fad35a)
- Bug 1204084 - Double tap gesture fails when tapping on a large element contained in an iframe or scrollable div. r=botond (71463b4cdf)
- Bug 1231517 - part 1, Move GetBoundingContentRect to nsLayoutUtils r=botond (3dbe9c6309)
- Bug 1231517 - part 2, Add support for APZ ZoomToRectBehavior flags r=kats (4a7f22a0cf)

dom/base/nsDOMWindowUtils.cpp

@@ -2808,8 +2808,8 @@ nsDOMWindowUtils::IsPartOfOpaqueLayer(nsIDOMElement* aElement, bool* aResult)
     return NS_ERROR_FAILURE;
   }
 
-  Layer* layer = FrameLayerBuilder::GetDebugSingleOldLayerForFrame(frame);
-  if (!layer || !layer->AsPaintedLayer()) {
+  PaintedLayer* layer = FrameLayerBuilder::GetDebugSingleOldPaintedLayerForFrame(frame);
+  if (!layer) {
     return NS_ERROR_FAILURE;
   }
 
@@ -2839,12 +2839,12 @@ nsDOMWindowUtils::NumberOfAssignedPaintedLayers(nsIDOMElement** aElements,
       return NS_ERROR_FAILURE;
     }
 
-    Layer* layer = FrameLayerBuilder::GetDebugSingleOldLayerForFrame(frame);
-    if (!layer || !layer->AsPaintedLayer()) {
+    PaintedLayer* layer = FrameLayerBuilder::GetDebugSingleOldPaintedLayerForFrame(frame);
+    if (!layer) {
       return NS_ERROR_FAILURE;
     }
 
-    layers.PutEntry(layer->AsPaintedLayer());
+    layers.PutEntry(layer);
   }
 
   *aResult = layers.Count();