Revert of Use element id's for animations

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index ad9321248946c465250f03c8be370239bc69fc71..f6ba036b0fba588ba276e462646a35220160c694 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -1521,52 +1521,36 @@
     }
 }
 
-// Some background on when you receive an element id or mutable properties.
-//
-// element id:
-//   If you have a compositor proxy, an animation, or you're a scroller (and
-//   might impl animate).
-//
-// mutable properties:
-//   Only if you have a compositor proxy.
-//
-// The element id for the scroll layers is assigned when they're constructed,
-// since this is unconditional. However, the element id for the primary layer as
-// well as the mutable properties for all layers may change according to the
-// rules above so we update those values here.
 void CompositedLayerMapping::updateElementIdAndCompositorMutableProperties()
 {
-    int elementId = 0;
-    uint32_t primaryMutableProperties = CompositorMutableProperty::kNone;
+    if (!RuntimeEnabledFeatures::compositorWorkerEnabled())
+        return;
+
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositedLayerMapping::updateElementId()");
+
+    uint64_t elementId = 0;
+    uint32_t mainMutableProperties = CompositorMutableProperty::kNone;
     uint32_t scrollMutableProperties = CompositorMutableProperty::kNone;
 
-    Node* owningNode = m_owningLayer.layoutObject()->generatingNode();
-    Element* owningElement = nullptr;
-    if (owningNode && owningNode->isElementNode())
-        owningElement = toElement(owningNode);
-
-    if (RuntimeEnabledFeatures::compositorWorkerEnabled() && owningElement && m_owningLayer.layoutObject()->style()->hasCompositorProxy()) {
-        uint32_t compositorMutableProperties = owningElement->compositorMutableProperties();
-        elementId = DOMNodeIds::idForNode(owningNode);
-        primaryMutableProperties = (CompositorMutableProperty::kOpacity | CompositorMutableProperty::kTransform) & compositorMutableProperties;
-        scrollMutableProperties = (CompositorMutableProperty::kScrollLeft | CompositorMutableProperty::kScrollTop) & compositorMutableProperties;
-    }
-
-    if (m_owningLayer.layoutObject()->style()->shouldCompositeForCurrentAnimations() && owningNode)
-        elementId = DOMNodeIds::idForNode(owningNode);
-
-    CompositorElementId compositorElementId;
-    if (elementId)
-        compositorElementId = createCompositorElementId(elementId, CompositorSubElementId::Primary);
-
-    m_graphicsLayer->setElementId(compositorElementId);
-    m_graphicsLayer->setCompositorMutableProperties(primaryMutableProperties);
-
-    // We always set the elementId for m_scrollingContentsLayer since it can be
-    // animated for smooth scrolling, so we don't need to set it conditionally
-    // here.
-    if (m_scrollingContentsLayer.get())
+    if (m_owningLayer.layoutObject()->style()->hasCompositorProxy()) {
+        if (Node* owningNode = m_owningLayer.layoutObject()->generatingNode()) {
+            if (owningNode->isElementNode()) {
+                Element* owningElement = toElement(owningNode);
+                uint32_t compositorMutableProperties = owningElement->compositorMutableProperties();
+                elementId = DOMNodeIds::idForNode(owningNode);
+                mainMutableProperties = (CompositorMutableProperty::kOpacity | CompositorMutableProperty::kTransform) & compositorMutableProperties;
+                scrollMutableProperties = (CompositorMutableProperty::kScrollLeft | CompositorMutableProperty::kScrollTop) & compositorMutableProperties;
+            }
+        }
+    }
+
+    m_graphicsLayer->setElementId(elementId);
+    m_graphicsLayer->setCompositorMutableProperties(mainMutableProperties);
+
+    if (m_scrollingContentsLayer.get()) {
+        m_scrollingContentsLayer->setElementId(elementId);
         m_scrollingContentsLayer->setCompositorMutableProperties(scrollMutableProperties);
+    }
 }
 
 bool CompositedLayerMapping::updateForegroundLayer(bool needsForegroundLayer)
@@ -1653,12 +1637,6 @@
 
             // Inner layer which renders the content that scrolls.
             m_scrollingContentsLayer = createGraphicsLayer(CompositingReasonLayerForScrollingContents);
-
-            if (Node* owningNode = m_owningLayer.layoutObject()->generatingNode()) {
-                m_scrollingContentsLayer->setElementId(createCompositorElementId(DOMNodeIds::idForNode(owningNode), CompositorSubElementId::Scroll));
-                m_scrollingContentsLayer->setCompositorMutableProperties(CompositorMutableProperty::kScrollLeft | CompositorMutableProperty::kScrollTop);
-            }
-
             m_scrollingLayer->addChild(m_scrollingContentsLayer.get());
 
             layerChanged = true;