Add a tuple of name, local name for hashing custom element definitions.

third_party/WebKit/Source/core/dom/custom/CustomElementDescriptor.h

Index: third_party/WebKit/Source/core/dom/custom/CustomElementDescriptor.h
diff --git a/third_party/WebKit/Source/core/dom/custom/CustomElementDescriptor.h b/third_party/WebKit/Source/core/dom/custom/CustomElementDescriptor.h
new file mode 100644
index 0000000000000000000000000000000000000000..520c559cab1c4fb3287d0bc927f81d4e22988e6b
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/custom/CustomElementDescriptor.h
@@ -0,0 +1,68 @@
+// 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.
+
+#ifndef CustomElementDescriptor_h
+#define CustomElementDescriptor_h
+
+#include "core/CoreExport.h"
+#include "wtf/Allocator.h"
+#include "wtf/HashTableDeletedValueType.h"
+#include "wtf/text/AtomicString.h"
+
+namespace blink {
+
+// Describes what elements a custom element definition applies to.
+//
+// There are two kinds of definitions: The first has its own tag name;
+// in this case the "name" (definition name) and local name (tag name)
+// are the same. The second kind customizes a built-in element; in
+// that case, the descriptor's local name will be a built-in element
+// name, or an unknown element name that is *not* a valid custom
+// element name.
+//
+// This type is used when the kind of custom element definition is
+// known, and generally the difference is important. For example, a
+// definition for "my-element", "my-element" must not be applied to an
+// element <button is="my-element">.
+class CORE_EXPORT CustomElementDescriptor final {
+    DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
+public:
+    CustomElementDescriptor()
+    {
+    }
+
+    CustomElementDescriptor(
+        const AtomicString& name,
+        const AtomicString& localName)
+        : m_name(name)
+        , m_localName(localName)
+    {
+    }
+
+    explicit CustomElementDescriptor(WTF::HashTableDeletedValueType value)
+        : m_name(value)
+    {
+    }
+
+    bool isHashTableDeletedValue() const
+    {
+        return m_name.isHashTableDeletedValue();
+    }
+
+    bool operator==(const CustomElementDescriptor& other) const
+    {
+        return m_name == other.m_name && m_localName == other.m_localName;
+    }
+
+    const AtomicString& name() const { return m_name; }
+    const AtomicString& localName() const { return m_localName; }
+
+private:
+    AtomicString m_name;
+    AtomicString m_localName;
+};
+
+} // namespace blink
+
+#endif // CustomElementDescriptor_h