Revert of Revert of Move preferred scrollbar style preference change listening from renderer to browser, 3 of 3.

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 47 matching lines @@
 }
 
 static bool supportsContentAreaScrolledInDirection()
 {
     static bool globalSupportsContentAreaScrolledInDirection = [NSClassFromString(@"NSScrollerImpPair") instancesRespondToSelector:@selector(contentAreaScrolledInDirection:)];
     return globalSupportsContentAreaScrolledInDirection;
 }
 
 static ScrollbarThemeMacOverlayAPI* macOverlayScrollbarTheme()
 {
-    RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(isScrollbarOverlayAPIAvailable());
+    RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(ScrollbarThemeMacCommon::isOverlayAPIAvailable());
     ScrollbarTheme* scrollbarTheme = ScrollbarTheme::theme();
     return !scrollbarTheme->isMockTheme() ? static_cast<ScrollbarThemeMacOverlayAPI*>(scrollbarTheme) : 0;
 }
 
 static ScrollbarPainter scrollbarPainterForScrollbar(Scrollbar* scrollbar)
 {
     if (ScrollbarThemeMacOverlayAPI* scrollbarTheme = macOverlayScrollbarTheme())
         return scrollbarTheme->painterForScrollbar(scrollbar);
 
     return nil;
@@ skipping 514 matching lines @@
 #if USE(RUBBER_BANDING)
     , m_scrollElasticityController(this)
     , m_snapRubberBandTimer(this, &ScrollAnimatorMac::snapRubberBandTimerFired)
 #endif
     , m_haveScrolledSincePageLoad(false)
     , m_needsScrollerStyleUpdate(false)
 {
     m_scrollAnimationHelperDelegate.adoptNS([[WebScrollAnimationHelperDelegate alloc] initWithScrollAnimator:this]);
     m_scrollAnimationHelper.adoptNS([[NSClassFromString(@"NSScrollAnimationHelper") alloc] initWithDelegate:m_scrollAnimationHelperDelegate.get()]);
 
-    if (isScrollbarOverlayAPIAvailable()) {
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         m_scrollbarPainterControllerDelegate.adoptNS([[WebScrollbarPainterControllerDelegate alloc] initWithScrollableArea:scrollableArea]);
         m_scrollbarPainterController = [[[NSClassFromString(@"NSScrollerImpPair") alloc] init] autorelease];
         [m_scrollbarPainterController.get() setDelegate:m_scrollbarPainterControllerDelegate.get()];
-        [m_scrollbarPainterController.get() setScrollerStyle:recommendedScrollerStyle()];
+        [m_scrollbarPainterController.get() setScrollerStyle:ScrollbarThemeMacCommon::recommendedScrollerStyle()];
     }
 }
 
 ScrollAnimatorMac::~ScrollAnimatorMac()
 {
-    if (isScrollbarOverlayAPIAvailable()) {
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         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;
     }
 }
 
@@ skipping 102 matching lines @@
 void ScrollAnimatorMac::notifyPositionChanged(const FloatSize& delta)
 {
     notifyContentAreaScrolled(delta);
     ScrollAnimator::notifyPositionChanged(delta);
 }
 
 void ScrollAnimatorMac::contentAreaWillPaint() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() contentAreaWillDraw];
 }
 
 void ScrollAnimatorMac::mouseEnteredContentArea() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() mouseEnteredContentArea];
 }
 
 void ScrollAnimatorMac::mouseExitedContentArea() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() mouseExitedContentArea];
 }
 
 void ScrollAnimatorMac::mouseMovedInContentArea() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() mouseMovedInContentArea];
 }
 
 void ScrollAnimatorMac::mouseEnteredScrollbar(Scrollbar* scrollbar) const
 {
     // At this time, only legacy scrollbars needs to send notifications here.
-    if (recommendedScrollerStyle() != NSScrollerStyleLegacy)
+    if (ScrollbarThemeMacCommon::recommendedScrollerStyle() != NSScrollerStyleLegacy)
         return;
 
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
 
-    if (isScrollbarOverlayAPIAvailable()) {
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         if (!supportsUIStateTransitionProgress())
             return;
         if (ScrollbarPainter painter = scrollbarPainterForScrollbar(scrollbar))
             [painter mouseEnteredScroller];
     }
 }
 
 void ScrollAnimatorMac::mouseExitedScrollbar(Scrollbar* scrollbar) const
 {
     // At this time, only legacy scrollbars needs to send notifications here.
-    if (recommendedScrollerStyle() != NSScrollerStyleLegacy)
+    if (ScrollbarThemeMacCommon::recommendedScrollerStyle() != NSScrollerStyleLegacy)
         return;
 
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
 
-    if (isScrollbarOverlayAPIAvailable()) {
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         if (!supportsUIStateTransitionProgress())
             return;
         if (ScrollbarPainter painter = scrollbarPainterForScrollbar(scrollbar))
             [painter mouseExitedScroller];
     }
 }
 
 void ScrollAnimatorMac::willStartLiveResize()
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() startLiveResize];
 }
 
 void ScrollAnimatorMac::contentsResized() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() contentAreaDidResize];
 }
 
 void ScrollAnimatorMac::willEndLiveResize()
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() endLiveResize];
 }
 
 void ScrollAnimatorMac::contentAreaDidShow() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() windowOrderedIn];
 }
 
 void ScrollAnimatorMac::contentAreaDidHide() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() windowOrderedOut];
 }
 
 void ScrollAnimatorMac::didBeginScrollGesture() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() beginScrollGesture];
 }
 
 void ScrollAnimatorMac::didEndScrollGesture() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (isScrollbarOverlayAPIAvailable())
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         [m_scrollbarPainterController.get() endScrollGesture];
 }
 
 void ScrollAnimatorMac::mayBeginScrollGesture() const
 {
     if (!scrollableArea()->scrollbarsCanBeActive())
         return;
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     [m_scrollbarPainterController.get() beginScrollGesture];
     [m_scrollbarPainterController.get() contentAreaScrolled];
 }
 
 void ScrollAnimatorMac::finishCurrentScrollAnimations()
 {
-    if (isScrollbarOverlayAPIAvailable()) {
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         [m_scrollbarPainterController.get() hideOverlayScrollers];
     }
 }
 
 void ScrollAnimatorMac::didAddVerticalScrollbar(Scrollbar* scrollbar)
 {
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     ScrollbarPainter painter = scrollbarPainterForScrollbar(scrollbar);
     if (!painter)
         return;
 
     ASSERT(!m_verticalScrollbarPainterDelegate);
     m_verticalScrollbarPainterDelegate.adoptNS([[WebScrollbarPainterDelegate alloc] initWithScrollbar:scrollbar]);
 
     [painter setDelegate:m_verticalScrollbarPainterDelegate.get()];
     [m_scrollbarPainterController.get() setVerticalScrollerImp:painter];
     if (scrollableArea()->inLiveResize())
         [painter setKnobAlpha:1];
 }
 
 void ScrollAnimatorMac::willRemoveVerticalScrollbar(Scrollbar* scrollbar)
 {
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     ScrollbarPainter painter = scrollbarPainterForScrollbar(scrollbar);
     if (!painter)
         return;
 
     ASSERT(m_verticalScrollbarPainterDelegate);
     [m_verticalScrollbarPainterDelegate.get() invalidate];
     m_verticalScrollbarPainterDelegate = nullptr;
 
     [painter setDelegate:nil];
     [m_scrollbarPainterController.get() setVerticalScrollerImp:nil];
 }
 
 void ScrollAnimatorMac::didAddHorizontalScrollbar(Scrollbar* scrollbar)
 {
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     ScrollbarPainter painter = scrollbarPainterForScrollbar(scrollbar);
     if (!painter)
         return;
 
     ASSERT(!m_horizontalScrollbarPainterDelegate);
     m_horizontalScrollbarPainterDelegate.adoptNS([[WebScrollbarPainterDelegate alloc] initWithScrollbar:scrollbar]);
 
     [painter setDelegate:m_horizontalScrollbarPainterDelegate.get()];
     [m_scrollbarPainterController.get() setHorizontalScrollerImp:painter];
     if (scrollableArea()->inLiveResize())
         [painter setKnobAlpha:1];
 }
 
 void ScrollAnimatorMac::willRemoveHorizontalScrollbar(Scrollbar* scrollbar)
 {
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     ScrollbarPainter painter = scrollbarPainterForScrollbar(scrollbar);
     if (!painter)
         return;
 
     ASSERT(m_horizontalScrollbarPainterDelegate);
     [m_horizontalScrollbarPainterDelegate.get() invalidate];
     m_horizontalScrollbarPainterDelegate = nullptr;
 
     [painter setDelegate:nil];
     [m_scrollbarPainterController.get() setHorizontalScrollerImp:nil];
 }
 
 bool ScrollAnimatorMac::shouldScrollbarParticipateInHitTesting(Scrollbar* scrollbar)
 {
     // Non-overlay scrollbars should always participate in hit testing.
-    if (recommendedScrollerStyle() != NSScrollerStyleOverlay)
+    if (ScrollbarThemeMacCommon::recommendedScrollerStyle() != NSScrollerStyleOverlay)
         return true;
 
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return true;
 
     if (scrollbar->isAlphaLocked())
         return true;
 
     // Overlay scrollbars should participate in hit testing whenever they are at all visible.
     ScrollbarPainter painter = scrollbarPainterForScrollbar(scrollbar);
     if (!painter)
         return false;
     return [painter knobAlpha] > 0;
 }
 
 void ScrollAnimatorMac::notifyContentAreaScrolled(const FloatSize& delta)
 {
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     // This function is called when a page is going into the page cache, but the page 
     // isn't really scrolling in that case. We should only pass the message on to the
     // ScrollbarPainterController when we're really scrolling on an active page.
     if (scrollableArea()->scrollbarsCanBeActive())
         sendContentAreaScrolledSoon(delta);
 }
 
 void ScrollAnimatorMac::cancelAnimations()
 {
     m_haveScrolledSincePageLoad = false;
 
-    if (isScrollbarOverlayAPIAvailable()) {
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         if (scrollbarPaintTimerIsActive())
             stopScrollbarPaintTimer();
         [m_horizontalScrollbarPainterDelegate.get() cancelAnimations];
         [m_verticalScrollbarPainterDelegate.get() cancelAnimations];
     }
 }
 
 void ScrollAnimatorMac::handleWheelEventPhase(PlatformWheelEventPhase phase)
 {
     // This may not have been set to true yet if the wheel event was handled by the ScrollingTree,
@@ skipping 167 matching lines @@
 }
 
 void ScrollAnimatorMac::snapRubberBandTimerFired(Timer<ScrollAnimatorMac>*)
 {
     m_scrollElasticityController.snapRubberBandTimerFired();
 }
 #endif
 
 void ScrollAnimatorMac::setIsActive()
 {
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     if (!m_needsScrollerStyleUpdate)
         return;
 
     updateScrollerStyle();
 }
 
 void ScrollAnimatorMac::updateScrollerStyle()
 {
-    if (!isScrollbarOverlayAPIAvailable())
+    if (!ScrollbarThemeMacCommon::isOverlayAPIAvailable())
         return;
 
     if (!scrollableArea()->scrollbarsCanBeActive()) {
         m_needsScrollerStyleUpdate = true;
         return;
     }
 
     ScrollbarThemeMacOverlayAPI* macTheme = macOverlayScrollbarTheme();
     if (!macTheme) {
         m_needsScrollerStyleUpdate = false;
@@ skipping 55 matching lines @@
     return m_initialScrollbarPaintTimer.isActive();
 }
 
 void ScrollAnimatorMac::stopScrollbarPaintTimer()
 {
     m_initialScrollbarPaintTimer.stop();
 }
 
 void ScrollAnimatorMac::initialScrollbarPaintTimerFired(Timer<ScrollAnimatorMac>*)
 {
-    if (isScrollbarOverlayAPIAvailable()) {
+    if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         // To force the scrollbars to flash, we have to call hide first. Otherwise, the ScrollbarPainterController
         // might think that the scrollbars are already showing and bail early.
         [m_scrollbarPainterController.get() hideOverlayScrollers];
         [m_scrollbarPainterController.get() flashScrollers];
     }
 }
 
 void ScrollAnimatorMac::sendContentAreaScrolledSoon(const FloatSize& delta)
 {
     m_contentAreaScrolledTimerScrollDelta = delta;
@@ skipping 17 matching lines @@
     if (Scrollbar* verticalScrollbar = m_scrollableArea->verticalScrollbar())
         rectInViewCoordinates = verticalScrollbar->convertToContainingView(scrollerThumb);
 
     if (rectInViewCoordinates == m_visibleScrollerThumbRect)
         return;
 
     m_visibleScrollerThumbRect = rectInViewCoordinates;
 }
 
 bool ScrollAnimatorMac::canUseCoordinatedScrollbar() {
-    return isScrollbarOverlayAPIAvailable();
+    return ScrollbarThemeMacCommon::isOverlayAPIAvailable();
 }
 
 } // namespace WebCore