Set distribution recalc flag when a slot assignment changes

third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp

Index: third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
diff --git a/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp b/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
index 6ee8312c6e27b0a1ac53b8d98a7d51a2eb5a4222..16ad5ad6d2d00a296052bad77cc4e04fac595305 100644
--- a/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
+++ b/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
@@ -7,6 +7,7 @@
 #include "core/HTMLNames.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/NodeTraversal.h"
+#include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/InsertionPoint.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/html/HTMLSlotElement.h"
@@ -86,6 +87,8 @@ void SlotAssignment::assign(Node& hostChild, HTMLSlotElement& slot)
         slot.appendDistributedNodesFrom(toHTMLSlotElement(hostChild));
     else
         slot.appendDistributedNode(hostChild);
+    if (slot.isChildOfV1ShadowHost())
+        slot.parentElementShadow()->setNeedsDistributionRecalc();
 }
 
 DEFINE_TRACE(SlotAssignment)