Implement script-side of callback reactions for Custom Elements V1

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

Index: third_party/WebKit/Source/core/dom/custom/CustomElementsRegistryTest.cpp
diff --git a/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistryTest.cpp b/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistryTest.cpp
index 10b013e3b67970222b1a9c107a09862fcb14fbe4..da2245a69f8079d9bbb4d32740889534d396ee82 100644
--- a/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistryTest.cpp
+++ b/third_party/WebKit/Source/core/dom/custom/CustomElementsRegistryTest.cpp
@@ -267,6 +267,9 @@ public:
     LogUpgradeDefinition(const CustomElementDescriptor& descriptor)
         : TestCustomElementDefinition(descriptor)
     {
+        m_observedAttributes.add("attr1");
+        m_observedAttributes.add("attr2");
+        m_observedAttributes.add(HTMLNames::contenteditableAttr.localName());
     }
 
     DEFINE_INLINE_VIRTUAL_TRACE()
@@ -308,7 +311,6 @@ public:
 
     bool hasConnectedCallback() const override { return true; }
     bool hasDisconnectedCallback() const override { return true; }
-    bool hasAttributeChangedCallback(const QualifiedName&) const override { return true; }
 
     void runConnectedCallback(Element* element) override
     {