Devirtualize Frame::domWindow().

third_party/WebKit/Source/core/frame/RemoteDOMWindow.h

Index: third_party/WebKit/Source/core/frame/RemoteDOMWindow.h
diff --git a/third_party/WebKit/Source/core/frame/RemoteDOMWindow.h b/third_party/WebKit/Source/core/frame/RemoteDOMWindow.h
index 2507461fc94756cda86f09a6cfa5c583a5285159..13c653847e8753f521417ed4ee5835053d27e586 100644
--- a/third_party/WebKit/Source/core/frame/RemoteDOMWindow.h
+++ b/third_party/WebKit/Source/core/frame/RemoteDOMWindow.h
@@ -7,6 +7,7 @@
 
 #include "core/frame/DOMWindow.h"
 #include "core/frame/RemoteFrame.h"
+#include "wtf/Assertions.h"
 
 namespace blink {
 
@@ -109,6 +110,12 @@ class RemoteDOMWindow final : public DOMWindow {
   Member<RemoteFrame> m_frame;
 };
 
+DEFINE_TYPE_CASTS(RemoteDOMWindow,
+                  DOMWindow,
+                  x,
+                  x->isRemoteDOMWindow(),
+                  x.isRemoteDOMWindow());
+
 }  // namespace blink
 
 #endif  // DOMWindow_h