Introduce CustomElementRegistry#get() method

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

Index: third_party/WebKit/Source/core/dom/custom/CustomElementDefinition.h
diff --git a/third_party/WebKit/Source/core/dom/custom/CustomElementDefinition.h b/third_party/WebKit/Source/core/dom/custom/CustomElementDefinition.h
index e410349ac24f66484daacbb7c199e68be1822b60..04197473208f283a648134871b46914dc8134fd9 100644
--- a/third_party/WebKit/Source/core/dom/custom/CustomElementDefinition.h
+++ b/third_party/WebKit/Source/core/dom/custom/CustomElementDefinition.h
@@ -12,6 +12,9 @@
 
 namespace blink {
 
+class ScriptState;
+class ScriptValue;

[dominicc (has gone to gerrit), 2016/05/31 06:01:50]

Is it possible to return by value without a complete definition?

[yosin_UTC9, 2016/05/31 09:16:57]

It works, but users of CED needs to include "ScriptValue.h". I changed to add
#include "ScriptValue.h" here.

+
 class CORE_EXPORT CustomElementDefinition
     : public GarbageCollectedFinalized<CustomElementDefinition> {
     WTF_MAKE_NONCOPYABLE(CustomElementDefinition);
@@ -21,6 +24,8 @@ public:
 
     const CustomElementDescriptor& descriptor() { return m_descriptor; }
 
+    virtual ScriptValue getConstructor(ScriptState*) = 0;

[dominicc (has gone to gerrit), 2016/05/31 06:01:51]

Write a C++ unit test that exercises this.

[yosin_UTC9, 2016/05/31 09:16:57]

Since, getConstructor() is used for implementing CER.get() and it is tested by
layout test.

Writing C++ test for getConstructor() is heavy, since it requires lots of thing,
e.g. DummyPageHolder to have ScriptCER, evaluate script to get constructor.
So, I would like to postpone having C++ test until we have script-free version
of getConstructor().

+
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 
 private: