compositor-worker: plumb element id and mutable properties

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 b8440dc009530511a66b0bc3962c79e57523656f..05be3ec30996d6f9aadf78b2db08b70c8eb12529 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -65,6 +65,7 @@
 #include "platform/graphics/paint/CullRect.h"
 #include "platform/graphics/paint/PaintController.h"
 #include "platform/graphics/paint/TransformDisplayItem.h"
+#include "public/platform/WebCompositorMutableProperties.h"
 #include "wtf/CurrentTime.h"
 #include "wtf/text/StringBuilder.h"
 
@@ -557,6 +558,8 @@ bool CompositedLayerMapping::updateGraphicsLayerConfiguration()
     if (layerConfigChanged || maskLayerChanged)
         updatePaintingPhases();
 
+    updateElementIdAndMutableProperties();
+
     return layerConfigChanged;
 }
 
@@ -744,6 +747,7 @@ void CompositedLayerMapping::updateGraphicsLayerGeometry(const PaintLayer* compo
     updateContentsRect();
     updateBackgroundColor();
     updateDrawsContent();
+    updateElementIdAndMutableProperties();
     updateContentsOpaque();
     updateAfterPartResize();
     updateRenderingContext();
@@ -1506,6 +1510,34 @@ void CompositedLayerMapping::updateShouldFlattenTransform()
     }
 }
 
+void CompositedLayerMapping::updateElementIdAndMutableProperties()
+{
+    if (!RuntimeEnabledFeatures::compositorWorkerEnabled())
+        return;
+
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("compositor-worker"), "CompositedLayerMapping::updateElementId()");
+
+    uint64_t elementId = 0;
+    uint32_t mainMutableProperties = WebCompositorMutablePropertyNone;
+    uint32_t scrollMutableProperties = WebCompositorMutablePropertyNone;
+
+    if (m_owningLayer.layoutObject()->style()->hasCompositorProxy()) {
+        if (Node* owningNode = m_owningLayer.layoutObject()->generatingNode()) {
+            elementId = DOMNodeIds::idForNode(owningNode);
+            mainMutableProperties = WebCompositorMutablePropertyOpacity | WebCompositorMutablePropertyTransform;
+            scrollMutableProperties = WebCompositorMutablePropertyScrollLeft | WebCompositorMutablePropertyScrollTop;
+        }
+    }
+
+    m_graphicsLayer->setElementId(elementId);

[chrishtr, 2015/11/24 16:22:50]

Can an element which is indirectly composited end up with a CW? If so you need
to add CW as a reason to prevent squashing.

[Ian Vollick, 2015/11/25 18:28:45]

Nope, a CompositorProxy is a direct compositing reason.

+    m_graphicsLayer->setMutableProperties(mainMutableProperties);
+
+    if (m_scrollingContentsLayer.get()) {
+        m_scrollingContentsLayer->setElementId(elementId);
+        m_scrollingContentsLayer->setMutableProperties(scrollMutableProperties);
+    }
+}
+
 bool CompositedLayerMapping::updateForegroundLayer(bool needsForegroundLayer)
 {
     bool layerChanged = false;