Support remote objects in WorldSafeV8Reference

Support remote objects in WorldSafeV8Reference by skipping the world check when creation context is not available.

Since ScriptValue is backed by WorldSafeV8Reference since r701030, remote objects may be assigned to WorldSafeV8References.

Bug: 1009159
Change-Id: I1117dffcd9a09279ea6add1d45f56ac69c6dfa25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1832844Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Keishi Hattori <keishi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#701491}

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

@@ -41,8 +41,12 @@ void WorldSafeV8ReferenceInternal::MaybeCheckCreationContextWorld(
   if (!value->IsObject())
     return;
 
-  ScriptState* script_state =
-      ScriptState::From(value.As<v8::Object>()->CreationContext());
+  v8::Local<v8::Context> context = value.As<v8::Object>()->CreationContext();
+  // Creation context is null if the value is a remote object.
+  if (context.IsEmpty())
+    return;
+
+  ScriptState* script_state = ScriptState::From(context);
   CHECK_EQ(&world, &script_state->World());
 }