Expose worklet on Window through attribute renderWorklet.

third_party/WebKit/Source/modules/worklet/DOMWindowWorklet.cpp

Index: third_party/WebKit/Source/modules/worklet/DOMWindowWorklet.cpp
diff --git a/third_party/WebKit/Source/modules/worklet/DOMWindowWorklet.cpp b/third_party/WebKit/Source/modules/worklet/DOMWindowWorklet.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..34c6e5c84830255faa62eecaa3e3378d901d2718
--- /dev/null
+++ b/third_party/WebKit/Source/modules/worklet/DOMWindowWorklet.cpp
@@ -0,0 +1,56 @@
+// Copyright 2016 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.
+
+#include "modules/worklet/DOMWindowWorklet.h"
+
+#include "core/frame/LocalDOMWindow.h"
+#include "core/frame/LocalFrame.h"
+#include "modules/worklet/Worklet.h"
+
+namespace blink {
+
+DOMWindowWorklet::DOMWindowWorklet(LocalDOMWindow& window)
+    : DOMWindowProperty(window.frame())
+{
+}
+
+DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(DOMWindowWorklet);
+
+const char* DOMWindowWorklet::supplementName()
+{
+    return "DOMWindowWorklet";
+}
+
+// static
+DOMWindowWorklet& DOMWindowWorklet::from(LocalDOMWindow& window)
+{
+    DOMWindowWorklet* supplement = static_cast<DOMWindowWorklet*>(WillBeHeapSupplement<LocalDOMWindow>::from(window, supplementName()));
+    if (!supplement) {
+        supplement = new DOMWindowWorklet(window);
+        provideTo(window, supplementName(), adoptPtrWillBeNoop(supplement));
+    }
+    return *supplement;
+}
+
+// static
+Worklet* DOMWindowWorklet::renderWorklet(ExecutionContext* executionContext, DOMWindow& window)
+{
+    return from(toLocalDOMWindow(window)).renderWorklet(executionContext);
+}
+
+Worklet* DOMWindowWorklet::renderWorklet(ExecutionContext* executionContext) const
+{
+    if (!m_renderWorklet && frame())
+        m_renderWorklet = Worklet::create(executionContext);
+    return m_renderWorklet.get();
+}
+
+DEFINE_TRACE(DOMWindowWorklet)
+{
+    visitor->trace(m_renderWorklet);
+    WillBeHeapSupplement<LocalDOMWindow>::trace(visitor);
+    DOMWindowProperty::trace(visitor);
+}
+
+} // namespace blink