Blink Support for Overlay Scrollbar Animation

Source/platform/scroll/ScrollableArea.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2008, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 14 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "platform/scroll/ScrollableArea.h"
 
+#include "platform/TraceEvent.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/geometry/FloatPoint.h"
+#include "platform/scroll/ScrollbarStateTransitionAnimator.h"
 #include "platform/scroll/ScrollbarTheme.h"
 #include "wtf/PassOwnPtr.h"
 
-#include "platform/TraceEvent.h"
 
 static const int kPixelsPerLineStep = 40;
 static const float kMinFractionToStepWhenPaging = 0.875f;
 
 namespace WebCore {
 
 struct SameSizeAsScrollableArea {
     virtual ~SameSizeAsScrollableArea();
     unsigned damageBits : 2;
     IntRect scrollbarDamage[2];
     void* pointer;
+    void* stateTranstionAnimatorPointer;

[abarth-chromium, 2014/06/16 22:47:04]

The point of having this struct here is to keep the size of this struct small. 
Is this feature worth the boat to this datastructure?

     unsigned bitfields : 16;
     IntPoint origin;
 };
 
 COMPILE_ASSERT(sizeof(ScrollableArea) == sizeof(SameSizeAsScrollableArea), ScrollableArea_should_stay_small);
 
 int ScrollableArea::pixelsPerLineStep()
 {
     return kPixelsPerLineStep;
 }
@@ skipping 26 matching lines @@
 }
 
 ScrollAnimator* ScrollableArea::scrollAnimator() const
 {
     if (!m_scrollAnimator)
         m_scrollAnimator = ScrollAnimator::create(const_cast<ScrollableArea*>(this));
 
     return m_scrollAnimator.get();
 }
 
+ScrollbarStateTransitionAnimator* ScrollableArea::scrollbarStateTransitionAnimator() const
+{
+    if (hasOverlayScrollbars() && !m_scrollbarStateTransitionAnimator)
+        m_scrollbarStateTransitionAnimator = ScrollbarStateTransitionAnimator::create(const_cast<ScrollableArea*>(this));
+
+    return m_scrollbarStateTransitionAnimator.get();
+}
+
+bool ScrollableArea::isDuringStateTransitionAnimation() const
+{
+    return hasOverlayScrollbars() && existingScrollbarStateTransitionAnimator() && existingScrollbarStateTransitionAnimator()->isDuringStateTransitionAnimation();
+}
+
+void ScrollableArea::stateTransitionInProgress()
+{
+    if (isDuringStateTransitionAnimation()) {
+        double progress = existingScrollbarStateTransitionAnimator()->stateTransitionProgress();
+        blink::WebThemeEngine::State startState = existingScrollbarStateTransitionAnimator()->stateTransitionStartState();
+        blink::WebThemeEngine::State endState = existingScrollbarStateTransitionAnimator()->stateTransitionEndState();
+
+        if (Scrollbar* verticalScrollbar = this->verticalScrollbar()) {
+            verticalScrollbar->updateStateTransitionData(startState, endState, progress);
+        }
+
+        if (Scrollbar* horizontalScrollbar = this->horizontalScrollbar()) {
+            horizontalScrollbar->updateStateTransitionData(startState, endState, progress);
+        }
+    }
+}
+
 void ScrollableArea::setScrollOrigin(const IntPoint& origin)
 {
     if (m_scrollOrigin != origin) {
         m_scrollOrigin = origin;
         m_scrollOriginChanged = true;
     }
 }
 
 GraphicsLayer* ScrollableArea::layerForContainer() const
 {
@@ skipping 161 matching lines @@
 
 void ScrollableArea::mouseMovedInContentArea() const
 {
     if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
         scrollAnimator->mouseMovedInContentArea();
 }
 
 void ScrollableArea::mouseEnteredScrollbar(Scrollbar* scrollbar) const
 {
     scrollAnimator()->mouseEnteredScrollbar(scrollbar);
+    if (ScrollbarStateTransitionAnimator* animator = scrollbarStateTransitionAnimator())
+        animator->mouseEnteredScrollbar(scrollbar);
 }
 
 void ScrollableArea::mouseExitedScrollbar(Scrollbar* scrollbar) const
 {
     scrollAnimator()->mouseExitedScrollbar(scrollbar);
+    if (ScrollbarStateTransitionAnimator* animator = scrollbarStateTransitionAnimator())
+        animator->mouseExitedScrollbar(scrollbar);
 }
 
 void ScrollableArea::contentAreaDidShow() const
 {
     if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
         scrollAnimator->contentAreaDidShow();
 }
 
 void ScrollableArea::contentAreaDidHide() const
 {
@@ skipping 91 matching lines @@
 bool ScrollableArea::hasLayerForVerticalScrollbar() const
 {
     return layerForVerticalScrollbar();
 }
 
 bool ScrollableArea::hasLayerForScrollCorner() const
 {
     return layerForScrollCorner();
 }
 
-void ScrollableArea::serviceScrollAnimations()
+void ScrollableArea::serviceScrollbarAnimations()
 {
     if (ScrollAnimator* scrollAnimator = existingScrollAnimator())
         scrollAnimator->serviceScrollAnimations();
+    if (ScrollbarStateTransitionAnimator* animator = existingScrollbarStateTransitionAnimator())
+        animator->serviceAnimations();
 }
 
 IntRect ScrollableArea::visibleContentRect(IncludeScrollbarsInRect scrollbarInclusion) const
 {
     int verticalScrollbarWidth = 0;
     int horizontalScrollbarHeight = 0;
 
     if (scrollbarInclusion == IncludeScrollbars) {
         if (Scrollbar* verticalBar = verticalScrollbar())
             verticalScrollbarWidth = !verticalBar->isOverlayScrollbar() ? verticalBar->width() : 0;
@@ skipping 30 matching lines @@
 {
     return scrollSize(orientation);
 }
 
 float ScrollableArea::pixelStep(ScrollbarOrientation) const
 {
     return 1;
 }
 
 } // namespace WebCore