Forbid passing empty v8::Local to ScriptValue constructor

Forbid passing empty v8::Local to ScriptValue constructor.
This will make the rules consistent with WorldSafeV8Reference's constructor.

Change-Id: Id0f0302025eb8397a5ebcef78ea91671cda1e453
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1847412
Commit-Queue: Keishi Hattori <keishi@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704136}

third_party/blink/renderer/bindings/core/v8/script_value.h

@@ -70,14 +70,10 @@ class CORE_EXPORT ScriptValue final {
 
   ScriptValue() = default;
 
-  // TODO(rikaf): Forbid passing empty v8::Local<v8::Value> to ScriptValue's
-  // ctor.
   ScriptValue(v8::Isolate* isolate, v8::Local<v8::Value> value)
       : isolate_(isolate),
-        value_(value.IsEmpty()
-                   ? MakeGarbageCollected<WorldSafeV8ReferenceWrapper>()
-                   : MakeGarbageCollected<WorldSafeV8ReferenceWrapper>(isolate,
-                                                                       value)) {
+        value_(
+            MakeGarbageCollected<WorldSafeV8ReferenceWrapper>(isolate, value)) {
     DCHECK(isolate_);
   }
 

third_party/blink/renderer/bindings/core/v8/to_v8_for_core.h

@@ -77,8 +77,10 @@ inline v8::Local<v8::Value> ToV8(const DisallowNewWrapper<ScriptValue>* value,
 // and ScriptValue
 template <typename T>
 inline ScriptValue ScriptValue::From(ScriptState* script_state, T&& value) {
-  return ScriptValue(script_state->GetIsolate(),
-                     ToV8(std::forward<T>(value), script_state));
+  v8::Local<v8::Value> v8_value = ToV8(std::forward<T>(value), script_state);
+  if (v8_value.IsEmpty())
+    return ScriptValue();
+  return ScriptValue(script_state->GetIsolate(), v8_value);
 }
 
 }  // namespace blink

third_party/blink/renderer/bindings/core/v8/world_safe_v8_reference.h

@@ -59,6 +59,7 @@ class WorldSafeV8Reference final {
 
   explicit WorldSafeV8Reference(v8::Isolate* isolate, v8::Local<V8Type> value)
       : v8_reference_(isolate, value) {
+    DCHECK(!value.IsEmpty());
     // Basically, |world_| is a world when this V8 reference is created.
     // However, when this V8 reference isn't created in context and value is
     // object, we set |world_| to a value's creation cotext's world.

third_party/blink/renderer/core/dom/document.cc

@@ -1631,6 +1631,8 @@ ScriptValue Document::registerElement(ScriptState* script_state,
   V0CustomElementConstructorBuilder constructor_builder(script_state, options);
   RegistrationContext()->RegisterElement(this, &constructor_builder, name,
                                          exception_state);
+  if (exception_state.HadException())
+    return ScriptValue();
   return constructor_builder.BindingsReturnValue();
 }