Split ScrollbarThemeMac into Overlay and NonOverlay subclasses

Source/core/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 45 matching lines @@
     static bool globalSupportsExpansionTransitionProgress = [NSClassFromString(@"NSScrollerImp") instancesRespondToSelector:@selector(expansionTransitionProgress)];
     return globalSupportsExpansionTransitionProgress;
 }
 
 static bool supportsContentAreaScrolledInDirection()
 {
     static bool globalSupportsContentAreaScrolledInDirection = [NSClassFromString(@"NSScrollerImpPair") instancesRespondToSelector:@selector(contentAreaScrolledInDirection:)];
     return globalSupportsContentAreaScrolledInDirection;
 }
 
-static ScrollbarThemeMac* macScrollbarTheme()
+static ScrollbarThemeMacOverlay* macOverlayScrollbarTheme()
 {
     ScrollbarTheme* scrollbarTheme = ScrollbarTheme::theme();
-    return !scrollbarTheme->isMockTheme() ? static_cast<ScrollbarThemeMac*>(scrollbarTheme) : 0;
+    return !scrollbarTheme->isMockTheme() ? static_cast<ScrollbarThemeMacOverlay*>(scrollbarTheme) : 0;

[enne (OOO), 2013/07/31 18:23:59]

So, I *think* this is only for overlay scrollbars, but am not 100% sure.  Do you
have more confidence that this is the case?

Should there be some ASSERT here that the overlay API is supported?

[ccameron, 2013/07/31 20:26:57]

Yes, there should be an ASSERT added. Done.

 }
 
 static ScrollbarPainter scrollbarPainterForScrollbar(Scrollbar* scrollbar)
 {
-    if (ScrollbarThemeMac* scrollbarTheme = macScrollbarTheme())
+    if (ScrollbarThemeMacOverlay* scrollbarTheme = macOverlayScrollbarTheme())
         return scrollbarTheme->painterForScrollbar(scrollbar);
 
     return nil;
 }
 
 @interface NSObject (ScrollAnimationHelperDetails)
 - (id)initWithDelegate:(id)delegate;
 - (void)_stopRun;
 - (BOOL)_isAnimating;
 - (NSPoint)targetOrigin;
@@ skipping 1097 matching lines @@
 void ScrollAnimatorMac::updateScrollerStyle()
 {
     if (!isScrollbarOverlayAPIAvailable())
         return;
 
     if (!scrollableArea()->scrollbarsCanBeActive()) {
         m_needsScrollerStyleUpdate = true;
         return;
     }
 
-    ScrollbarThemeMac* macTheme = macScrollbarTheme();
+    ScrollbarThemeMacOverlay* macTheme = macOverlayScrollbarTheme();
     if (!macTheme) {
         m_needsScrollerStyleUpdate = false;
         return;
     }
 
     NSScrollerStyle newStyle = [m_scrollbarPainterController.get() scrollerStyle];
 
     if (Scrollbar* verticalScrollbar = scrollableArea()->verticalScrollbar()) {
         verticalScrollbar->invalidate();
 
@@ skipping 89 matching lines @@
         return;
 
     m_visibleScrollerThumbRect = rectInViewCoordinates;
 }
 
 bool ScrollAnimatorMac::canUseCoordinatedScrollbar() {
     return isScrollbarOverlayAPIAvailable();
 }
 
 } // namespace WebCore