Use element id's for animations

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

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1510 matching lines @@
     // Regardless, mark the graphics layer, scrolling layer and scrolling block
     // selection layer (if they exist) as not flattening. Having them flatten
     // causes unclipped render surfaces which cause bugs.
     // http://crbug.com/521768
     if (hasScrollingLayer()) {
         m_graphicsLayer->setShouldFlattenTransform(false);
         m_scrollingLayer->setShouldFlattenTransform(false);
     }
 }
 
+// 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()
 {
-    if (!RuntimeEnabledFeatures::compositorWorkerEnabled())
-        return;
-
-    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositedLayerMapping::updateElementId()");
-
-    uint64_t elementId = 0;
-    uint32_t mainMutableProperties = CompositorMutableProperty::kNone;
+    int elementId = 0;
+    uint32_t primaryMutableProperties = CompositorMutableProperty::kNone;
     uint32_t scrollMutableProperties = CompositorMutableProperty::kNone;
 
-    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;
-            }
-        }
+    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;
     }
 
-    m_graphicsLayer->setElementId(elementId);
-    m_graphicsLayer->setCompositorMutableProperties(mainMutableProperties);
+    if (m_owningLayer.layoutObject()->style()->shouldCompositeForCurrentAnimations() && owningNode)
+        elementId = DOMNodeIds::idForNode(owningNode);
 
-    if (m_scrollingContentsLayer.get()) {
-        m_scrollingContentsLayer->setElementId(elementId);
+    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())
         m_scrollingContentsLayer->setCompositorMutableProperties(scrollMutableProperties);
-    }
 }
 
 bool CompositedLayerMapping::updateForegroundLayer(bool needsForegroundLayer)
 {
     bool layerChanged = false;
     if (needsForegroundLayer) {
         if (!m_foregroundLayer) {
             m_foregroundLayer = createGraphicsLayer(CompositingReasonLayerForForeground);
             layerChanged = true;
         }
@@ skipping 66 matching lines @@
     bool layerChanged = false;
     if (needsScrollingLayers) {
         if (!m_scrollingLayer) {
             // Outer layer which corresponds with the scroll view.
             m_scrollingLayer = createGraphicsLayer(CompositingReasonLayerForScrollingContainer);
             m_scrollingLayer->setDrawsContent(false);
             m_scrollingLayer->setMasksToBounds(true);
 
             // 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;
             if (scrollingCoordinator) {
                 scrollingCoordinator->scrollableAreaScrollLayerDidChange(m_owningLayer.getScrollableArea());
                 scrollingCoordinator->scrollableAreasDidChange();
             }
         }
     } else if (m_scrollingLayer) {
         m_scrollingLayer = nullptr;
@@ skipping 990 matching lines @@
     } else if (graphicsLayer == m_scrollingContentsLayer.get()) {
         name = "Scrolling Contents Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink