Cleanup: Move ChromeClient::m_lastSetMouseCursorForTesting to ChromeClientImpl.

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 e3408f02b7aba1e4d6c67590acff2a542841c7b5..2f7c8f736cb180341b0bbdeb211ec43d269a8b36 100644
--- a/Source/core/loader/EmptyClients.h
+++ b/Source/core/loader/EmptyClients.h
@@ -142,7 +142,8 @@ public:
 
     void runOpenPanel(LocalFrame*, PassRefPtr<FileChooser>) override;
 
-    void setCursorInternal(const Cursor&) override { }
+    void setCursor(const Cursor&) override { }
+    Cursor lastSetCursorForTesting() const override { return pointerCursor(); }
 
     void attachRootGraphicsLayer(GraphicsLayer*, LocalFrame* localRoot) override { }