Let Dart code running in Sky add events to the trace timeline

sky/engine/core/frame/LocalDOMWindow.h

 /*
  * Copyright (C) 2006, 2007, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 49 matching lines @@
 class LocalFrame;
 class Location;
 class MediaQueryList;
 class Node;
 class Page;
 class RequestAnimationFrameCallback;
 class ScheduledAction;
 class Screen;
 class ScriptCallStack;
 class StyleMedia;
+class Tracing;
 
 enum PageshowEventPersistence {
     PageshowEventNotPersisted = 0,
     PageshowEventPersisted = 1
 };
 
 enum SetLocationLocking { LockHistoryBasedOnGestureState, LockHistoryAndBackForwardList };
 
 class LocalDOMWindow final : public RefCounted<LocalDOMWindow>, public EventTargetWithInlineData, public DOMWindowBase64, public FrameDestructionObserver, public Supplementable<LocalDOMWindow>, public LifecycleContext<LocalDOMWindow> {
     DEFINE_WRAPPERTYPEINFO();
@@ skipping 37 matching lines @@
 
     int outerHeight() const;
     int outerWidth() const;
     int innerHeight() const;
     int innerWidth() const;
     int screenX() const;
     int screenY() const;
     int screenLeft() const { return screenX(); }
     int screenTop() const { return screenY(); }
 
+    Tracing& tracing() const;
+
     // FIXME(sky): keeping self for now since js-test.html uses it.
     LocalDOMWindow* window() const;
 
     // DOM Level 2 AbstractView Interface
 
     Document* document() const;
 
     // CSSOM View Module
 
     StyleMedia& styleMedia() const;
@@ skipping 88 matching lines @@
     RefPtr<Document> m_document;
 
 #if ENABLE(ASSERT)
     bool m_hasBeenReset;
 #endif
 
     HashSet<DOMWindowProperty*> m_properties;
 
     mutable RefPtr<Screen> m_screen;
     mutable RefPtr<Location> m_location;
-
+    mutable RefPtr<Tracing> m_tracing;
     mutable RefPtr<DOMWindowCSS> m_css;
 
     RefPtr<DOMWindowEventQueue> m_eventQueue;
 };
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_CORE_FRAME_LOCALDOMWINDOW_H_