Upgrade in-document custom elements when an element is defined.

third_party/WebKit/Source/core/dom/custom/CEReactionsScope.cpp

Index: third_party/WebKit/Source/core/dom/custom/CEReactionsScope.cpp
diff --git a/third_party/WebKit/Source/core/dom/custom/CEReactionsScope.cpp b/third_party/WebKit/Source/core/dom/custom/CEReactionsScope.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..817a91900e441d1eedb4811fce7e46ddebee5e99
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/custom/CEReactionsScope.cpp
@@ -0,0 +1,32 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/dom/custom/CEReactionsScope.h"
+
+#include "core/dom/Document.h"
+#include "core/dom/Element.h"
+#include "core/dom/custom/CustomElementReactionStack.h"
+#include "core/frame/FrameHost.h"
+
+namespace blink {
+
+CEReactionsScope* CEReactionsScope::s_topOfStack = nullptr;
+
+void CEReactionsScope::enqueue(
+    Element* element,
+    CustomElementReaction* reaction)
+{
+    if (!m_frameHost.get()) {
+        m_frameHost = element->document().frameHost();
+        m_frameHost->customElementReactionStack().push();
+    }
+    m_frameHost->customElementReactionStack().enqueue(element, reaction);
+}
+
+void CEReactionsScope::invokeReactions()
+{
+    m_frameHost->customElementReactionStack().popInvokingReactions();
+}
+
+} // namespace blink