Replace hand-written IDBObserverCallback with auto-generated code

third_party/WebKit/Source/bindings/modules/v8/custom/V8IDBObserverCustom.cpp

 // 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.
 
 #include "bindings/modules/v8/V8IDBObserver.h"
 
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
-#include "bindings/modules/v8/V8IDBObserverCallback.h"
+#include "bindings/core/v8/V8PrivateProperty.h"
+#include "bindings/modules/v8/IDBObserverCallback.h"
 #include "bindings/modules/v8/V8IDBObserverInit.h"
 
 namespace blink {
 
 void V8IDBObserver::constructorCustom(
     const v8::FunctionCallbackInfo<v8::Value>& info) {
   ExceptionState exceptionState(
       info.GetIsolate(), ExceptionState::ConstructionContext, "IDBObserver");
 
   if (UNLIKELY(info.Length() < 1)) {
@@ skipping 15 matching lines @@
     exceptionState.throwTypeError("parameter 2 ('options') is not an object.");
     return;
   }
 
   IDBObserverInit idbObserverInit;
   V8IDBObserverInit::toImpl(info.GetIsolate(), info[1], idbObserverInit,
                             exceptionState);
   if (exceptionState.hadException())
     return;
 
+  v8::Local<v8::Function> v8Callback = v8::Local<v8::Function>::Cast(info[0]);
   IDBObserverCallback* callback =
-      new V8IDBObserverCallback(v8::Local<v8::Function>::Cast(info[0]), wrapper,
-                                ScriptState::current(info.GetIsolate()));
-  IDBObserver* observer = IDBObserver::create(*callback, idbObserverInit);
+      IDBObserverCallback::create(info.GetIsolate(), v8Callback);
+  IDBObserver* observer = IDBObserver::create(
+      ScriptState::forReceiverObject(info), callback, idbObserverInit);
   if (exceptionState.hadException())
     return;
   DCHECK(observer);
+  // TODO(bashi): Do we need this?
+  V8PrivateProperty::getIDBObserverCallback(info.GetIsolate())

[bashi, 2016/10/07 07:07:26]

Auto-generated IDBObserverCallback calls setPhantom() for |v8Callback|. I'm not
sure we need this.

[haraken, 2016/10/07 07:23:35]

The point is that we need to add a strong reference from IDBObserver's wrapper
to the callback. Before this CL, we were doing that by using V8PrivateProperty.
After this CL, we're expected to do that using
V8IDBObserverCallback::setWrapperReference.

So I think what we should do is:

- Add the strong reference with V8IDBObserverCallback::setWrapperReference.
- Remove this custom binding.

[bashi, 2016/10/07 07:28:38]

OK, let me ask another question. Who/when to call setWrapperReference() ?

We want to remove this custom binding but I think we should do it in follow-up
CLs (Maybe after all hand-written code for callbacks are gone).

+      .set(info.GetIsolate()->GetCurrentContext(), wrapper, v8Callback);
   v8SetReturnValue(info,
                    V8DOMWrapper::associateObjectWithWrapper(
                        info.GetIsolate(), observer, &wrapperTypeInfo, wrapper));
 }
 
 }  // namespace blink