Report accurate Overscroll on handleWheel.

Source/core/input/EventHandler.cpp

Index: Source/core/input/EventHandler.cpp
diff --git a/Source/core/input/EventHandler.cpp b/Source/core/input/EventHandler.cpp
index ed72ddf7134747ec0f7302532c2da5e16c164a68..78c49deb7214528211a84c585d6b427e5df5d1e6 100644
--- a/Source/core/input/EventHandler.cpp
+++ b/Source/core/input/EventHandler.cpp
@@ -1782,7 +1782,10 @@ bool EventHandler::handleWheelEvent(const PlatformWheelEvent& event)
     if (!view)
         return false;
 
-    if (view->scrollableArea()->handleWheel(event).didScroll())
+    ScrollResult scrollResult = view->scrollableArea()->handleWheel(event);
+    if (m_frame->settings() && m_frame->settings()->elasticOverscrollEnabled())
+        handleOverscroll(scrollResult);
+    if (scrollResult.didScroll())
         RETURN_WHEEL_EVENT_HANDLED();
 
     return false;
@@ -2255,17 +2258,23 @@ void EventHandler::resetOverscroll(bool didScrollX, bool didScrollY)
         m_accumulatedRootOverscroll.setHeight(0);
 }
 
-void EventHandler::handleOverscroll(const ScrollResult& scrollResult, const PlatformGestureEvent& gestureEvent)
+void EventHandler::handleOverscroll(const ScrollResult& scrollResult, const FloatPoint& position, const FloatSize& velocity)
 {
     if (m_frame->isMainFrame() && m_frame->view() && m_frame->view()->scrollableArea()) {
         ScrollableArea* scrollablearea = m_frame->view()->scrollableArea();
-        // Set unusedDelta if axis is scrollable, else set 0 to ensure overflow is not reported on non-scrollable axes.
-        FloatSize unusedDelta(scrollablearea->scrollSize(HorizontalScrollbar) ? scrollResult.unusedScrollDeltaX : 0, scrollablearea->scrollSize(VerticalScrollbar) ? scrollResult.unusedScrollDeltaY : 0);
+        FloatSize unusedDelta;
+        if (m_frame->settings() && m_frame->settings()->elasticOverscrollEnabled()) {
+            // ElasticOverscroll should be applied on non-Scrollable axis.
+            unusedDelta.setWidth(scrollResult.unusedScrollDeltaX);
+            unusedDelta.setHeight(scrollResult.unusedScrollDeltaY);
+        } else {
+            // In Case of android set unusedDelta if axis is scrollable, else set 0 to ensure overflow is not reported on non-scrollable axes.
+            unusedDelta.setWidth(scrollablearea->scrollSize(HorizontalScrollbar) ? scrollResult.unusedScrollDeltaX : 0);
+            unusedDelta.setHeight(scrollablearea->scrollSize(VerticalScrollbar) ? scrollResult.unusedScrollDeltaY : 0);
+        }
         resetOverscroll(scrollResult.didScrollX, scrollResult.didScrollY);
         if (unusedDelta != FloatSize()) {
             m_accumulatedRootOverscroll += unusedDelta;
-            FloatPoint position = FloatPoint(gestureEvent.position().x(), gestureEvent.position().y());
-            FloatSize velocity = FloatSize(gestureEvent.velocityX(), gestureEvent.velocityY());
             m_frame->chromeClient().didOverscroll(unusedDelta, m_accumulatedRootOverscroll, position, velocity);
         }
     }
@@ -2354,7 +2363,9 @@ bool EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gesture
 
     // Try to scroll the frame view.
     ScrollResult scrollResult = m_frame->applyScrollDelta(delta, false);
-    handleOverscroll(scrollResult, gestureEvent);
+    FloatPoint position = FloatPoint(gestureEvent.position().x(), gestureEvent.position().y());
+    FloatSize velocity = FloatSize(gestureEvent.velocityX(), gestureEvent.velocityY());
+    handleOverscroll(scrollResult, position, velocity);
     if (scrollResult.didScroll()) {
         setFrameWasScrolledByUser();
         return true;