Revert of Remove invert viewport scroll order setting from Blink

third_party/WebKit/Source/core/frame/RootFrameViewport.h

Index: third_party/WebKit/Source/core/frame/RootFrameViewport.h
diff --git a/third_party/WebKit/Source/core/frame/RootFrameViewport.h b/third_party/WebKit/Source/core/frame/RootFrameViewport.h
index 2b57cc9d294b4669df4d350035fa815c705fe52b..fca0dfccb1dacc74e2331db415f0311ed267c240 100644
--- a/third_party/WebKit/Source/core/frame/RootFrameViewport.h
+++ b/third_party/WebKit/Source/core/frame/RootFrameViewport.h
@@ -25,9 +25,9 @@
     USING_FAST_MALLOC_WILL_BE_REMOVED(RootFrameViewport);
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(RootFrameViewport);
 public:
-    static PassOwnPtrWillBeRawPtr<RootFrameViewport> create(ScrollableArea& visualViewport, ScrollableArea& layoutViewport)
+    static PassOwnPtrWillBeRawPtr<RootFrameViewport> create(ScrollableArea& visualViewport, ScrollableArea& layoutViewport, bool invertScrollOrder = false)
     {
-        return adoptPtrWillBeNoop(new RootFrameViewport(visualViewport, layoutViewport));
+        return adoptPtrWillBeNoop(new RootFrameViewport(visualViewport, layoutViewport, invertScrollOrder));
     }
 
     DECLARE_VIRTUAL_TRACE();
@@ -71,7 +71,7 @@
     ScrollBehavior scrollBehaviorStyle() const override;
 
 private:
-    RootFrameViewport(ScrollableArea& visualViewport, ScrollableArea& layoutViewport);
+    RootFrameViewport(ScrollableArea& visualViewport, ScrollableArea& layoutViewport, bool invertScrollOrder);
 
     DoublePoint scrollOffsetFromScrollAnimators() const;
 
@@ -87,6 +87,10 @@
 
     RawPtrWillBeMember<ScrollableArea> m_visualViewport;
     RawPtrWillBeMember<ScrollableArea> m_layoutViewport;
+
+    // Experimental flag. If the experiment is enabled, scroll the visual viewport first,
+    // the bubble scrolls to the layout viewport.
+    bool m_invertScrollOrder;
 };
 
 } // namespace blink