compositor-worker: Force elements to grow a layer when a CompositorProxy is created.

Source/core/dom/Node.h

Index: Source/core/dom/Node.h
diff --git a/Source/core/dom/Node.h b/Source/core/dom/Node.h
index a509181a6c46ecbbdbbf54593155cae77c39aad5..3bcb1417fcdba40dc60db3c9f0bd032ea818c90a 100644
--- a/Source/core/dom/Node.h
+++ b/Source/core/dom/Node.h
@@ -673,6 +673,9 @@ public:
     void setAlreadySpellChecked(bool flag) { setFlag(flag, AlreadySpellCheckedFlag); }
     bool isAlreadySpellChecked() { return getFlag(AlreadySpellCheckedFlag); }
 
+    void setHasCompositorProxy(bool flag) { setFlag(flag, HasCompositorProxyFlag); }
+    bool hasCompositorProxy() const { return getFlag(HasCompositorProxyFlag); }
+
     bool isFinishedParsingChildren() const { return getFlag(IsFinishedParsingChildrenFlag); }
 
     DECLARE_VIRTUAL_TRACE();
@@ -728,6 +731,7 @@ private:
         HasSyntheticAttrChildNodesFlag = 1 << 26,
         HasEventTargetDataFlag = 1 << 27,
         AlreadySpellCheckedFlag = 1 << 28,
+        HasCompositorProxyFlag = 1 << 29,
 
         DefaultNodeFlags = IsFinishedParsingChildrenFlag | ChildNeedsStyleRecalcFlag | NeedsReattachStyleChange
     };