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

third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp b/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
index 0b3fc1a545382631c9d4b4993a3e165bcfa2e098..ae5d8e41f19e34536c1bda4be73988007efa3e4e 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
@@ -44,6 +44,19 @@
 
 namespace blink {
 
+struct SameSizeAsScrollableArea {
+  virtual ~SameSizeAsScrollableArea();
+#if ENABLE(ASSERT)
+  VerifyEagerFinalization verifyEager;
+#endif
+  Member<void*> pointer[2];
+  unsigned bitfields : 17;
+  IntPoint origin;
+};
+
+static_assert(sizeof(ScrollableArea) == sizeof(SameSizeAsScrollableArea),
+              "ScrollableArea should stay small");
+
 int ScrollableArea::pixelsPerLineStep(HostWindow* host) {
   if (!host)
     return kPixelsPerLineStep;
@@ -66,20 +79,17 @@
       m_horizontalScrollbarNeedsPaintInvalidation(false),
       m_verticalScrollbarNeedsPaintInvalidation(false),
       m_scrollCornerNeedsPaintInvalidation(false),
-      m_scrollbarsHidden(false),
-      m_scrollbarCaptured(false) {}
+      m_scrollbarsHidden(false) {}
 
 ScrollableArea::~ScrollableArea() {}
 
-void ScrollableArea::clearScrollableArea() {
+void ScrollableArea::clearScrollAnimators() {
 #if OS(MACOSX)
   if (m_scrollAnimator)
     m_scrollAnimator->dispose();
 #endif
   m_scrollAnimator.clear();
   m_programmaticScrollAnimator.clear();
-  if (m_fadeOverlayScrollbarsTimer)
-    m_fadeOverlayScrollbarsTimer->stop();
 }
 
 ScrollAnimatorBase& ScrollableArea::scrollAnimator() const {
@@ -322,27 +332,12 @@
     scrollAnimator->mouseMovedInContentArea();
 }
 
-void ScrollableArea::mouseEnteredScrollbar(Scrollbar& scrollbar) {
+void ScrollableArea::mouseEnteredScrollbar(Scrollbar& scrollbar) const {
   scrollAnimator().mouseEnteredScrollbar(scrollbar);
-  // Restart the fade out timer.
-  showOverlayScrollbars();
-}
-
-void ScrollableArea::mouseExitedScrollbar(Scrollbar& scrollbar) {
+}
+
+void ScrollableArea::mouseExitedScrollbar(Scrollbar& scrollbar) const {
   scrollAnimator().mouseExitedScrollbar(scrollbar);
-}
-
-void ScrollableArea::mouseCapturedScrollbar() {
-  m_scrollbarCaptured = true;
-  showOverlayScrollbars();
-  if (m_fadeOverlayScrollbarsTimer)
-    m_fadeOverlayScrollbarsTimer->stop();
-}
-
-void ScrollableArea::mouseReleasedScrollbar() {
-  m_scrollbarCaptured = false;
-  // This will kick off the fade out timer.
-  showOverlayScrollbars();
 }
 
 void ScrollableArea::contentAreaDidShow() const {
@@ -383,7 +378,6 @@
 }
 
 void ScrollableArea::contentsResized() {
-  showOverlayScrollbars();
   if (ScrollAnimatorBase* scrollAnimator = existingScrollAnimator())
     scrollAnimator->contentsResized();
 }
@@ -544,40 +538,8 @@
 void ScrollableArea::setScrollbarsHidden(bool hidden) {
   if (m_scrollbarsHidden == static_cast<unsigned>(hidden))
     return;
-
   m_scrollbarsHidden = hidden;
-  scrollbarVisibilityChanged();
-}
-
-void ScrollableArea::fadeOverlayScrollbarsTimerFired(TimerBase*) {
-  setScrollbarsHidden(true);
-}
-
-void ScrollableArea::showOverlayScrollbars() {
-  if (!ScrollbarTheme::theme().usesOverlayScrollbars())
-    return;
-
-  setScrollbarsHidden(false);
-
-  const double timeUntilDisable =
-      ScrollbarTheme::theme().overlayScrollbarFadeOutDelaySeconds() +
-      ScrollbarTheme::theme().overlayScrollbarFadeOutDurationSeconds();
-
-  // If the overlay scrollbars don't fade out, don't do anything. This is the
-  // case for the mock overlays used in tests and on Mac, where the fade-out is
-  // animated in ScrollAnimatorMac.
-  if (!timeUntilDisable)
-    return;
-
-  if (!m_fadeOverlayScrollbarsTimer) {
-    m_fadeOverlayScrollbarsTimer.reset(new Timer<ScrollableArea>(
-        this, &ScrollableArea::fadeOverlayScrollbarsTimerFired));
-  }
-
-  if (!m_scrollbarCaptured) {
-    m_fadeOverlayScrollbarsTimer->startOneShot(timeUntilDisable,
-                                               BLINK_FROM_HERE);
-  }
+  didChangeScrollbarsHidden();
 }
 
 IntRect ScrollableArea::visibleContentRect(