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

sky/engine/core/frame/LocalDOMWindow.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 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 39 matching lines @@
 #include "sky/engine/core/events/HashChangeEvent.h"
 #include "sky/engine/core/events/PageTransitionEvent.h"
 #include "sky/engine/core/frame/DOMWindowLifecycleNotifier.h"
 #include "sky/engine/core/frame/FrameConsole.h"
 #include "sky/engine/core/frame/FrameHost.h"
 #include "sky/engine/core/frame/FrameView.h"
 #include "sky/engine/core/frame/LocalFrame.h"
 #include "sky/engine/core/frame/Location.h"
 #include "sky/engine/core/frame/Screen.h"
 #include "sky/engine/core/frame/Settings.h"
+#include "sky/engine/core/frame/Tracing.h"
 #include "sky/engine/core/inspector/ConsoleMessage.h"
 #include "sky/engine/core/loader/FrameLoaderClient.h"
 #include "sky/engine/core/page/ChromeClient.h"
 #include "sky/engine/core/page/EventHandler.h"
 #include "sky/engine/core/page/Page.h"
 #include "sky/engine/core/rendering/style/RenderStyle.h"
 #include "sky/engine/core/script/dart_controller.h"
 #include "sky/engine/platform/EventDispatchForbiddenScope.h"
 #include "sky/engine/platform/PlatformScreen.h"
 #include "sky/engine/platform/geometry/FloatRect.h"
@@ skipping 341 matching lines @@
     return &m_frame->console();
 }
 
 Location& LocalDOMWindow::location() const
 {
     if (!m_location)
         m_location = Location::create(m_frame);
     return *m_location;
 }
 
+Tracing& LocalDOMWindow::tracing() const
+{
+    if (!m_tracing)
+        m_tracing = Tracing::create();
+    return *m_tracing;
+}
+
 DOMSelection* LocalDOMWindow::getSelection()
 {
     return m_frame->document()->getSelection();
 }
 
 void LocalDOMWindow::focus()
 {
     if (!m_frame)
         return;
 
@@ skipping 288 matching lines @@
 {
     return static_cast<DOMWindowLifecycleNotifier&>(LifecycleContext<LocalDOMWindow>::lifecycleNotifier());
 }
 
 PassOwnPtr<LifecycleNotifier<LocalDOMWindow> > LocalDOMWindow::createLifecycleNotifier()
 {
     return DOMWindowLifecycleNotifier::create(this);
 }
 
 } // namespace blink