Revert of Implement overlay scrollbar fade out for non-composited scrollers.

third_party/WebKit/Source/platform/scroll/ScrollbarThemeOverlayMock.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 20 matching lines @@
 #ifndef ScrollbarThemeOverlayMock_h
 #define ScrollbarThemeOverlayMock_h
 
 #include "platform/scroll/ScrollbarThemeOverlay.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT ScrollbarThemeOverlayMock : public ScrollbarThemeOverlay {
  public:
   ScrollbarThemeOverlayMock()
-      : ScrollbarThemeOverlay(3, 4, DisallowHitTest, Color(128, 128, 128)),
-        m_delayInSeconds(0.0) {}
-
-  double overlayScrollbarFadeOutDelaySeconds() const override {
-    return m_delayInSeconds;
-  }
-  double overlayScrollbarFadeOutDurationSeconds() const override { return 0.0; }
-
-  void setOverlayScrollbarFadeOutDelay(double delayInSeconds) {
-    m_delayInSeconds = delayInSeconds;
-  }
+      : ScrollbarThemeOverlay(3, 4, DisallowHitTest, Color(128, 128, 128)) {}
 
  private:
-  double m_delayInSeconds;
   bool isMockTheme() const final { return true; }
 };
 
 }  // namespace blink
 #endif  // ScrollbarThemeOverlayMock_h