Support slotchange event

third_party/WebKit/Source/core/dom/Node.cpp

Index: third_party/WebKit/Source/core/dom/Node.cpp
diff --git a/third_party/WebKit/Source/core/dom/Node.cpp b/third_party/WebKit/Source/core/dom/Node.cpp
index 7ff26433da8eeb4b6d0e1727615d10484e84f811..69772ebcaa39dc19f2aef6f549855975134344fc 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -552,6 +552,12 @@ bool Node::needsDistributionRecalc() const
 }
 #endif
 
+void Node::updateAssignment()
+{
+    Node& root = shadowIncludingRoot();
+    root.recalcAssignment();
+}
+
 void Node::updateDistribution()
 {
     // Extra early out to avoid spamming traces.
@@ -564,6 +570,24 @@ void Node::updateDistribution()
         root.recalcDistribution();
 }
 
+void Node::recalcAssignment()

[hayato, 2016/04/18 07:16:31]

We do not want to call recalcAssignment recursively.

Given that we call updateAssignment in each DOM mutation, and the result of
assignments is purely a local effect within one node tree, I would rather call
assignV1() (or something else) for a node tree which would be directly affected,
in each DOM mutation.

[yuzuchan, 2016/04/18 09:43:27]

Thanks for the feedback! Done.

+{
+    if (isElementNode()) {
+        if (ElementShadow* shadow = toElement(this)->shadow()) {
+            if (shadow->isV1())
+                shadow->youngestShadowRoot().assignV1();
+        }
+    }
+
+    for (Node* child = firstChild(); child; child = child->nextSibling()) {
+        child->recalcAssignment();
+    }
+
+    for (ShadowRoot* root = youngestShadowRoot(); root; root = root->olderShadowRoot()) {
+        root->recalcAssignment();
+    }
+}
+
 void Node::recalcDistribution()
 {
     DCHECK(childNeedsDistributionRecalc());
@@ -947,6 +971,11 @@ bool Node::isChildOfV0ShadowHost() const
     return parentShadow && !parentShadow->isV1();
 }
 
+bool Node::isChildOfSlot() const
+{
+    return parentElement() && isHTMLSlotElement(parentElement());
+}
+
 Element* Node::shadowHost() const
 {
     if (ShadowRoot* root = containingShadowRoot())