Disable scroll anchoring if the user engages in a drag motion

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 a01daf62278610f29c3e50c34f0103e6fdb12b86..ce4eeb19f89b45e24be086631440e023851fb9b6 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp
@@ -270,6 +270,10 @@ void ScrollableArea::scrollPositionChanged(const DoublePoint& position, ScrollTy
     // Tell the derived class to scroll its contents.
     setScrollOffset(truncatedPosition, scrollType);
 
+    // If the scroll position is changed, the user is not dragging (e.g panning
+    // a map).
+    setUserMayHaveDragged(false);
+
     // Tell the scrollbars to update their thumb postions.
     // If the scrollbar does not have its own layer, it must always be
     // invalidated to reflect the new thumb position, even if the theme did not