Add API to send NSUserDefault values over IPC, while preserving current behavior

Source/platform/mac/ScrollAnimatorMac.mm

 /*
  * Copyright (C) 2010, 2011 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 670 matching lines @@
         BEGIN_BLOCK_OBJC_EXCEPTIONS;
         [m_scrollbarPainterControllerDelegate.get() invalidate];
         [m_scrollbarPainterController.get() setDelegate:nil];
         [m_horizontalScrollbarPainterDelegate.get() invalidate];
         [m_verticalScrollbarPainterDelegate.get() invalidate];
         [m_scrollAnimationHelperDelegate.get() invalidate];
         END_BLOCK_OBJC_EXCEPTIONS;
     }
 }
 
-static bool scrollAnimationEnabledForSystem()
-{
-    static bool initialized = false;
-    static bool enabled = true;
-    if (!initialized) {
-        // Check setting for OS X 10.8+.
-        id value = [[NSUserDefaults standardUserDefaults] objectForKey:@"NSScrollAnimationEnabled"];
-        // Check setting for OS X < 10.8.
-        if (!value)
-            value = [[NSUserDefaults standardUserDefaults] objectForKey:@"AppleScrollAnimationEnabled"];
-        if (value)
-            enabled = [value boolValue];
-        initialized = true;
-    }
-    return enabled;
-}
-
 ScrollResultOneDimensional ScrollAnimatorMac::userScroll(ScrollbarOrientation orientation, ScrollGranularity granularity, float step, float delta)
 {
+    bool scrollAnimationEnabledForSystem = static_cast<ScrollbarThemeMacCommon*>(
+                                               ScrollbarTheme::theme())
+                                               ->scrollAnimationEnabledForSystem();
     m_haveScrolledSincePageLoad = true;
 
-    if (!scrollAnimationEnabledForSystem() || !m_scrollableArea->scrollAnimatorEnabled())
+    if (!scrollAnimationEnabledForSystem || !m_scrollableArea->scrollAnimatorEnabled())
         return ScrollAnimator::userScroll(orientation, granularity, step, delta);
 
     if (granularity == ScrollByPixel || granularity == ScrollByPrecisePixel)
         return ScrollAnimator::userScroll(orientation, granularity, step, delta);
 
     float currentPos = orientation == HorizontalScrollbar ? m_currentPosX : m_currentPosY;
     float newPos = std::max<float>(std::min<float>(currentPos + (step * delta), m_scrollableArea->maximumScrollPosition(orientation)), m_scrollableArea->minimumScrollPosition(orientation));
     if (currentPos == newPos)
         return ScrollResultOneDimensional(false);
 
@@ skipping 441 matching lines @@
         return;
 
     m_visibleScrollerThumbRect = rectInViewCoordinates;
 }
 
 bool ScrollAnimatorMac::canUseCoordinatedScrollbar() {
     return ScrollbarThemeMacCommon::isOverlayAPIAvailable();
 }
 
 } // namespace blink