Remove internals.setEnableMockPagePopup().

Source/core/loader/EmptyClients.h

Index: Source/core/loader/EmptyClients.h
diff --git a/Source/core/loader/EmptyClients.h b/Source/core/loader/EmptyClients.h
index 1202e1272bf429c4428cf9ade8df3d8facf128fc..aacfb06c223055968f5a4e2b11f5b22813cb6f85 100644
--- a/Source/core/loader/EmptyClients.h
+++ b/Source/core/loader/EmptyClients.h
@@ -117,9 +117,7 @@ public:
 
     virtual bool hasOpenedPopup() const override { return false; }
     virtual PassRefPtrWillBeRawPtr<PopupMenu> createPopupMenu(LocalFrame&, PopupMenuClient*) const override;
-    virtual void setPagePopupDriver(PagePopupDriver*) override { }
-    virtual void resetPagePopupDriver() override { }
-    virtual PagePopupDriver* pagePopupDriver() const override { return nullptr; }
+    virtual DOMWindow* pagePopupWindowForTesting() const override { return nullptr; }
 
     virtual void setStatusbarText(const String&) override { }