Move middle-click autoscroll to synthetic fling.

third_party/WebKit/Source/core/input/MouseEventManager.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MouseEventManager_h
 #define MouseEventManager_h
 
 #include "core/CoreExport.h"
 #include "core/dom/SynchronousMutationObserver.h"
 #include "core/input/BoundaryEventDispatcher.h"
@@ skipping 108 matching lines @@
 
   // Returns whether pan is handled and resets the state on release.
   bool HandleSvgPanIfNeeded(bool is_release_event);
 
   void InvalidateClick();
 
   // TODO: These functions ideally should be private but the code needs more
   // refactoring to be able to remove the dependency from EventHandler.
   Node* GetNodeUnderMouse();
   bool IsMousePositionUnknown();
   IntPoint LastKnownMousePosition();

[bokan, 2017/06/15 17:40:13]

Should this eventually become a FloatPoint as well? i.e. is the only reason you
didn't make it so because it could affect current callers? If so, could you add
a comment/TODO?

[aelias_OOO_until_Jul13, 2017/06/15 22:19:54]

Yes.  I added a TODO.

+  FloatPoint LastKnownMousePositionGlobal();
 
   bool MousePressed();
   void SetMousePressed(bool);
 
   bool CapturesDragging() const;
   void SetCapturesDragging(bool);
 
   void SetMouseDownMayStartAutoscroll() {
     mouse_down_may_start_autoscroll_ = true;
   }
@@ skipping 64 matching lines @@
   const Member<LocalFrame> frame_;
   Member<ScrollManager> scroll_manager_;
 
   // The effective position of the mouse pointer.
   // See
   // https://w3c.github.io/pointerevents/#dfn-tracking-the-effective-position-of-the-legacy-mouse-pointer.
   Member<Node> node_under_mouse_;
 
   // The last mouse movement position this frame has seen in root frame
   // coordinates.
-  IntPoint last_known_mouse_position_;
-  IntPoint last_known_mouse_global_position_;
+  FloatPoint last_known_mouse_position_;
+  FloatPoint last_known_mouse_global_position_;
 
   unsigned is_mouse_position_unknown_ : 1;
   // Current button-press state for mouse/mouse-like-stylus.
   // TODO(crbug.com/563676): Buggy for chorded buttons.
   unsigned mouse_pressed_ : 1;
 
   unsigned mouse_down_may_start_autoscroll_ : 1;
   unsigned svg_pan_ : 1;
   unsigned captures_dragging_ : 1;
   unsigned mouse_down_may_start_drag_ : 1;
@@ skipping 12 matching lines @@
   WebMouseEvent mouse_down_;
 
   LayoutPoint drag_start_pos_;
 
   TaskRunnerTimer<MouseEventManager> fake_mouse_move_event_timer_;
 };
 
 }  // namespace blink
 
 #endif  // MouseEventManager_h