Implement CSSOM Smooth Scroll API

Source/core/rendering/RenderLayerScrollableArea.cpp

Index: Source/core/rendering/RenderLayerScrollableArea.cpp
diff --git a/Source/core/rendering/RenderLayerScrollableArea.cpp b/Source/core/rendering/RenderLayerScrollableArea.cpp
index db17dc86836e0e73505ae696e504cc2e811dff1c..587575edc38b027a23c3ffad0f6881cc2bcdd5ae 100644
--- a/Source/core/rendering/RenderLayerScrollableArea.cpp
+++ b/Source/core/rendering/RenderLayerScrollableArea.cpp
@@ -50,6 +50,7 @@
 #include "core/editing/FrameSelection.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/Settings.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
@@ -111,6 +112,7 @@ RenderLayerScrollableArea::~RenderLayerScrollableArea()
     if (LocalFrame* frame = box().frame()) {
         if (FrameView* frameView = frame->view()) {
             frameView->removeScrollableArea(this);
+            frameView->removeAnimatingScrollableArea(this);
         }
     }
 
@@ -518,6 +520,23 @@ int RenderLayerScrollableArea::pageStep(ScrollbarOrientation orientation) const
     return max(pageStep, 1);
 }
 
+void RenderLayerScrollableArea::registerForAnimation()
+{
+    box().frameView()->addAnimatingScrollableArea(this);
+}
+
+void RenderLayerScrollableArea::deregisterForAnimation()
+{
+    if (FrameView* frameView = box().frameView()) {
+        frameView->removeAnimatingScrollableArea(this);
+    }
+}
+
+bool RenderLayerScrollableArea::scheduleAnimation()
+{
+    return box().frameView()->scheduleAnimation();
+}
+
 RenderBox& RenderLayerScrollableArea::box() const
 {
     return *m_layer.renderBox();
@@ -564,11 +583,18 @@ void RenderLayerScrollableArea::computeScrollDimensions()
     setScrollOrigin(IntPoint(-scrollableLeftOverflow, -scrollableTopOverflow));
 }
 
-void RenderLayerScrollableArea::scrollToOffset(const IntSize& scrollOffset, ScrollOffsetClamping clamp)
+void RenderLayerScrollableArea::scrollToOffset(const IntSize& scrollOffset, ScrollOffsetClamping clamp, ScrollBehavior scrollBehavior)
 {
+    cancelProgrammaticScrollAnimation();
     IntSize newScrollOffset = clamp == ScrollOffsetClamped ? clampScrollOffset(scrollOffset) : scrollOffset;
-    if (newScrollOffset != adjustedScrollOffset())
-        scrollToOffsetWithoutAnimation(-scrollOrigin() + newScrollOffset);
+    if (scrollBehavior == ScrollBehaviorAuto)
+        scrollBehavior = box().style()->scrollBehavior();
+    if (newScrollOffset != adjustedScrollOffset()) {
+        if (scrollBehavior == ScrollBehaviorSmooth)
+            programmaticallyScrollSmoothlyToOffset(-scrollOrigin() + newScrollOffset);
+        else
+            scrollToOffsetWithoutAnimation(-scrollOrigin() + newScrollOffset);
+    }
 }
 
 void RenderLayerScrollableArea::updateAfterLayout()
@@ -1383,6 +1409,7 @@ void RenderLayerScrollableArea::resize(const PlatformEvent& evt, const LayoutSiz
 
 LayoutRect RenderLayerScrollableArea::exposeRect(const LayoutRect& rect, const ScrollAlignment& alignX, const ScrollAlignment& alignY)
 {
+    cancelProgrammaticScrollAnimation();
     LayoutRect localExposeRect(box().absoluteToLocalQuad(FloatQuad(FloatRect(rect)), UseTransforms).boundingBox());
     LayoutRect layerBounds(0, 0, box().clientWidth(), box().clientHeight());
     LayoutRect r = ScrollAlignment::getRectToExpose(layerBounds, localExposeRect, alignX, alignY);