Fix mouse cursor update timer to be page-global instead of per-frame

Source/core/page/Chrome.h

Index: Source/core/page/Chrome.h
diff --git a/Source/core/page/Chrome.h b/Source/core/page/Chrome.h
index 56de23be178098940946a4e6883bf984d07c1272..a38d91813f5e1c44881df8ad93187cdcd86847ad 100644
--- a/Source/core/page/Chrome.h
+++ b/Source/core/page/Chrome.h
@@ -72,6 +72,7 @@ public:
     void contentsSizeChanged(LocalFrame*, const IntSize&) const;
 
     void setCursor(const Cursor&);
+    Cursor getLastSetCursorForTesting() const;
 
     void setWindowRect(const IntRect&) const;
     IntRect windowRect() const;
@@ -138,6 +139,7 @@ private:
     Page* m_page;
     ChromeClient* m_client;
     Vector<PopupOpeningObserver*> m_popupOpeningObservers;
+    Cursor m_lastSetMouseCursorForTesting;
 };
 
 } // namespace blink