Dispatching errors across iframes don't match webplatform tests

third_party/WebKit/Source/bindings/core/v8/ScriptState.h

 // Copyright 2014 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.
 
 #ifndef ScriptState_h
 #define ScriptState_h
 
 #include "bindings/core/v8/ScopedPersistent.h"
 #include "bindings/core/v8/V8PerContextData.h"
 #include "core/CoreExport.h"
@@ skipping 165 matching lines @@
   void clear() {
     m_scriptState = nullptr;
     m_context.clear();
   }
 
  private:
   RefPtr<ScriptState> m_scriptState;
   ScopedPersistent<v8::Context> m_context;
 };
 
+class ScriptStateForErrorEvent {
+  STACK_ALLOCATED();
+  WTF_MAKE_NONCOPYABLE(ScriptStateForErrorEvent);
+
+ public:
+  static ScriptStateForErrorEvent* current() { return s_topOfStack; }
+
+  ScriptStateForErrorEvent(v8::Local<v8::Context> context)

[haraken, 2016/11/02 01:40:18]

Add explicit.

+      : m_prev(s_topOfStack),
+        m_isolate(context->GetIsolate()),
+        m_context(m_isolate, context) {
+    s_topOfStack = this;
+  }
+
+  ~ScriptStateForErrorEvent() {
+    s_topOfStack = s_topOfStack->m_prev;
+  }
+
+  ScriptState* scriptState() {
+    return ScriptState::from(m_context.newLocal(m_isolate));
+  }
+
+  v8::Local<v8::Context> context() const {
+    return m_context.newLocal(m_isolate);
+  }
+
+ private:
+  static ScriptStateForErrorEvent* s_topOfStack;
+  ScriptStateForErrorEvent* m_prev;
+
+  v8::Isolate* m_isolate;
+  ScopedPersistent<v8::Context> m_context;

[haraken, 2016/11/02 01:40:18]

You can use v8::Local<v8::Context> because ScriptStateForErrorEvent is used only
on the stack.

However, I'd prefer just storing RefPtr<ScriptState>. Then you don't need to
store v8::Isolate* since you can get it via m_scriptState->isolate().

+};
+
 }  // namespace blink
 
 #endif  // ScriptState_h