[DevTools] Show distribution for Shadow DOM V1.

third_party/WebKit/Source/core/html/HTMLSlotElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp b/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
index 670f3fe39413bcc268ea6467c16628e6b1adf8ff..51dd142e6540d68c6b1f7e9dea538d7a35291339 100644
--- a/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLSlotElement.cpp
@@ -40,6 +40,7 @@
 #include "core/dom/shadow/SlotAssignment.h"
 #include "core/events/Event.h"
 #include "core/html/AssignedNodesOptions.h"
+#include "core/inspector/InspectorInstrumentation.h"
 
 namespace blink {
 
@@ -306,6 +307,7 @@ void HTMLSlotElement::lazyReattachDistributedNodesIfNeeded()
             node->lazyReattachIfAttached();
         for (auto& node : m_distributedNodes)
             node->lazyReattachIfAttached();
+        InspectorInstrumentation::didPerformSlotDistribution(this);
     }
     m_oldDistributedNodes.clear();
 }