Implement ComputedStylePropertyMap for Typed OM.

third_party/WebKit/Source/core/css/cssom/WindowGetComputedStyle.h

Index: third_party/WebKit/Source/core/css/cssom/WindowGetComputedStyle.h
diff --git a/third_party/WebKit/Source/core/css/cssom/WindowGetComputedStyle.h b/third_party/WebKit/Source/core/css/cssom/WindowGetComputedStyle.h
new file mode 100644
index 0000000000000000000000000000000000000000..1fa20e89dd1043c07a060c5b3586906cee6e5a35
--- /dev/null
+++ b/third_party/WebKit/Source/core/css/cssom/WindowGetComputedStyle.h
@@ -0,0 +1,26 @@
+// 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.
+
+#ifndef WindowGetComputedStyle_h
+#define WindowGetComputedStyle_h
+
+#include "core/css/CSSComputedStyleDeclaration.h"
+#include "core/css/cssom/ComputedStylePropertyMap.h"
+
+namespace blink {
+
+class WindowGetComputedStyle {
+    STATIC_ONLY(WindowGetComputedStyle);
+public:
+    static StylePropertyMap* getComputedStyleMap(const DOMWindow&, Element* element, const String& pseudoElement)
+    {
+        DCHECK(element);
+        CSSComputedStyleDeclaration* computedStyleDeclaration = CSSComputedStyleDeclaration::create(element, false, pseudoElement);
+        return ComputedStylePropertyMap::create(computedStyleDeclaration);
+    }
+};
+
+} // namespace blink
+
+#endif // WindowGetComputedStyle_h