Move middle-click autoscroll to synthetic fling.

third_party/WebKit/Source/core/layout/LayoutBox.cpp

Index: third_party/WebKit/Source/core/layout/LayoutBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.cpp b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
index 1fd325601d713ad5dd94557677fbc2ae982ec446..716d5c01e2c21dc101bc702bf978ad352e7b47bd 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -637,7 +637,7 @@ static bool IsDisallowedAutoscroll(HTMLFrameOwnerElement* owner_element,
     HTMLFrameElementBase* frame_element_base =
         ToHTMLFrameElementBase(owner_element);
     if (Page* page = frame_view->GetFrame().GetPage()) {
-      return page->GetAutoscrollController().AutoscrollInProgress() &&
+      return page->GetAutoscrollController().SelectionAutoscrollInProgress() &&
              frame_element_base->ScrollingMode() == kScrollbarAlwaysOff;
     }
   }
@@ -737,7 +737,10 @@ void LayoutBox::ScrollRectToVisibleRecursive(
     return;
   }
 
-  if (GetFrame()->GetPage()->GetAutoscrollController().AutoscrollInProgress())
+  if (GetFrame()
+          ->GetPage()
+          ->GetAutoscrollController()
+          .SelectionAutoscrollInProgress())
     parent_box = EnclosingScrollableBox();
 
   if (parent_box) {