Devirtualize Frame::domWindow().

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

Index: third_party/WebKit/Source/core/frame/Frame.h
diff --git a/third_party/WebKit/Source/core/frame/Frame.h b/third_party/WebKit/Source/core/frame/Frame.h
index 098c6031594dbe2b41733332d83c1e893f2900d5..2abf68fc5c60aa0d19eb5f5e0fcef4d98be8a5b9 100644
--- a/third_party/WebKit/Source/core/frame/Frame.h
+++ b/third_party/WebKit/Source/core/frame/Frame.h
@@ -74,7 +74,6 @@ class CORE_EXPORT Frame : public GarbageCollectedFinalized<Frame> {
   virtual bool isLocalFrame() const = 0;
   virtual bool isRemoteFrame() const = 0;
 
-  virtual DOMWindow* domWindow() const = 0;
   virtual WindowProxy* windowProxy(DOMWrapperWorld&) = 0;
 
   virtual void navigate(Document& originDocument,
@@ -107,6 +106,8 @@ class CORE_EXPORT Frame : public GarbageCollectedFinalized<Frame> {
   void setOwner(FrameOwner* owner) { m_owner = owner; }
   HTMLFrameOwnerElement* deprecatedLocalOwner() const;
 
+  DOMWindow* domWindow() const { return m_domWindow; }
+
   FrameTree& tree() const;
   ChromeClient& chromeClient() const;
 
@@ -153,6 +154,7 @@ class CORE_EXPORT Frame : public GarbageCollectedFinalized<Frame> {
 
   Member<FrameHost> m_host;
   Member<FrameOwner> m_owner;
+  Member<DOMWindow> m_domWindow;
 
   bool m_isDetaching = false;