Introduce CustomElementRegistry#get() method

third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp

Index: third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
index d0d3bd051180dce7ef6a8ad89f2a005361ff7fe8..93ca9d23e96c6233a42f5fc39ccbf61c856dd09c 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptCustomElementDefinition.cpp
@@ -109,6 +109,7 @@ ScriptCustomElementDefinition::ScriptCustomElementDefinition(
     const v8::Local<v8::Object>& constructor,
     const v8::Local<v8::Object>& prototype)
     : CustomElementDefinition(descriptor)
+    , m_scriptState(scriptState)
     , m_constructor(scriptState->isolate(), constructor)
     , m_prototype(scriptState->isolate(), prototype)
 {
@@ -122,6 +123,7 @@ ScriptCustomElementDefinition::ScriptCustomElementDefinition(
 v8::Local<v8::Object> ScriptCustomElementDefinition::constructor(
     ScriptState* scriptState) const

[haraken, 2016/06/01 02:28:12]

ScriptState is not needed. You can just pass in an Isolate.

[yosin_UTC9, 2016/06/01 06:16:14]

I'll handle this change in another CL.

 {
+    DCHECK_EQ(m_scriptState, scriptState);
     DCHECK(!m_constructor.isEmpty());
     return m_constructor.newLocal(scriptState->isolate());
 }
@@ -129,8 +131,18 @@ v8::Local<v8::Object> ScriptCustomElementDefinition::constructor(
 v8::Local<v8::Object> ScriptCustomElementDefinition::prototype(
     ScriptState* scriptState) const
 {
+    DCHECK_EQ(m_scriptState, scriptState);
     DCHECK(!m_prototype.isEmpty());
     return m_prototype.newLocal(scriptState->isolate());
 }
 
+// CustomElementDefinition
+ScriptValue ScriptCustomElementDefinition::getConstructorForScript(
+    ScriptState* scriptState)
+{
+    if (m_scriptState != scriptState)
+        return ScriptValue();
+    return ScriptValue(scriptState, constructor(scriptState));

[haraken, 2016/06/01 02:28:12]

I guess this should be:

  return ScriptValue(m_scriptState, constructor(m_scriptState));

and you can remove the |scriptState| parameter from getConstructorForScript.

As far as I understand, CustomElementsRegistry should return a constructor
object of the context from which the CustomElementsRegistry is created. If that
is the case, you should just use m_scriptState.

Also I cannot imagine a scenario where |scriptState| is not equal to
|m_scriptState| (because get() is always called by JavaScript; it's never
asynchronously called back by DOM). Can it happen?

[yosin_UTC9, 2016/06/01 06:16:14]

AFAIK, No. I should not be happened.

+}
+
 } // namespace blink