Introduce CustomElementRegistry#get() method

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

Index: third_party/WebKit/Source/core/dom/custom/CustomElementsRegistry.cpp
diff --git a/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistry.cpp b/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistry.cpp
index 618fa6158733ce98c0e8a201fb189d03966b939a..4e78ee70b7b818ed31574651eac53a9c6f8afbe2 100644
--- a/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistry.cpp
+++ b/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistry.cpp
@@ -112,6 +112,20 @@ void CustomElementsRegistry::define(
     // 20: when-defined promise processing
 }
 
+// https://html.spec.whatwg.org/multipage/scripting.html#dom-customelementsregistry-get
+ScriptValue CustomElementsRegistry::get(
+    ScriptState* scriptState,
+    const AtomicString& name)
+{
+    CustomElementDefinition* definition = definitionForName(name);
+    if (!definition) {
+        // Binding layer converts |ScriptValue()| to script specific value,

[dominicc (has gone to gerrit), 2016/05/31 22:56:32]

Love this comment. Short and specific.

+        // e.g. |undefined| for v8.
+        return ScriptValue();
+    }
+    return definition->getConstructor(scriptState);
+}
+
 bool CustomElementsRegistry::v0NameIsDefined(const AtomicString& name) const
 {
     if (!m_v0)