Move middle-click autoscroll to synthetic fling.

third_party/WebKit/Source/core/page/AutoscrollController.h

Index: third_party/WebKit/Source/core/page/AutoscrollController.h
diff --git a/third_party/WebKit/Source/core/page/AutoscrollController.h b/third_party/WebKit/Source/core/page/AutoscrollController.h
index b2e5093b69416ef68d761c8e928d5be472eb161b..d4a34b6677c118acebb69a3cfe76a231fc99e8a5 100644
--- a/third_party/WebKit/Source/core/page/AutoscrollController.h
+++ b/third_party/WebKit/Source/core/page/AutoscrollController.h
@@ -27,6 +27,7 @@
 #define AutoscrollController_h
 
 #include "core/CoreExport.h"
+#include "platform/geometry/FloatPoint.h"
 #include "platform/geometry/FloatSize.h"
 #include "platform/geometry/IntPoint.h"
 #include "platform/heap/Handle.h"
@@ -35,21 +36,30 @@
 namespace blink {
 
 class LocalFrame;
-class LocalFrameView;
 class Node;
 class Page;
 class LayoutBox;
 class LayoutObject;
-class WebMouseEvent;
 
 enum AutoscrollType {
   kNoAutoscroll,
   kAutoscrollForDragAndDrop,
   kAutoscrollForSelection,
-  kAutoscrollForMiddleClickCanStop,
   kAutoscrollForMiddleClick,
 };
 
+enum MiddleClickMode {
+  // Middle button was just pressed but was neither released nor moved out of
+  // the deadzone yet.
+  kMiddleClickInitial,
+  // Mouse was moved out of the deadzone while still holding middle mouse
+  // button.  In this mode, we'll stop autoscrolling when it's released.
+  kMiddleClickHolding,
+  // Middle button was released while still in the deadzone.  In this mode,
+  // we'll stop autoscrolling when any button is clicked.
+  kMiddleClickToggled,
+};
+
 // AutscrollController handels autoscroll and middle click autoscroll for
 // EventHandler.
 class CORE_EXPORT AutoscrollController final
@@ -58,12 +68,10 @@ class CORE_EXPORT AutoscrollController final
   static AutoscrollController* Create(Page&);
   DECLARE_TRACE();
 
-  static const int kNoMiddleClickAutoscrollRadius = 15;
-
+  // Selection and drag-and-drop autoscroll.
   void Animate(double monotonic_frame_begin_time);
-  bool AutoscrollInProgress() const;
+  bool SelectionAutoscrollInProgress() const;
   bool AutoscrollInProgress(const LayoutBox*) const;
-  bool MiddleClickAutoscrollInProgress() const;
   void StartAutoscrollForSelection(LayoutObject*);
   void StopAutoscroll();
   void StopAutoscrollIfNeeded(LayoutObject*);
@@ -71,28 +79,37 @@ class CORE_EXPORT AutoscrollController final
   void UpdateDragAndDrop(Node* target_node,
                          const IntPoint& event_position,
                          TimeTicks event_time);
+
+  // Middle-click autoscroll.
+  void StartMiddleClickAutoscroll(LocalFrame*,
+                                  const FloatPoint& position,
+                                  const FloatPoint& position_global);
+  void HandleMouseMoveForMiddleClickAutoscroll(
+      LocalFrame*,
+      const FloatPoint& position_global,
+      bool is_middle_button);
   void HandleMouseReleaseForMiddleClickAutoscroll(LocalFrame*,
-                                                  const WebMouseEvent&);
-  void StartMiddleClickAutoscroll(LayoutBox*, const IntPoint&);
+                                                  bool is_middle_button);
+  void StopMiddleClickAutoscroll(LocalFrame*);
+  bool MiddleClickAutoscrollInProgress() const;
 
  private:
   explicit AutoscrollController(Page&);
 
-  void StartAutoscroll();
-
-  void UpdateMiddleClickAutoscrollState(
-      LocalFrameView*,
-      const IntPoint& last_known_mouse_position);
-  FloatSize CalculateAutoscrollDelta();
-
   Member<Page> page_;
-  LayoutBox* autoscroll_layout_object_;
-  LayoutBox* pressed_layout_object_;
-  AutoscrollType autoscroll_type_;
+  AutoscrollType autoscroll_type_ = kNoAutoscroll;
+
+  // Selection and drag-and-drop autoscroll.
+  void ScheduleMainThreadAnimation();
+  LayoutBox* autoscroll_layout_object_ = nullptr;
+  LayoutBox* pressed_layout_object_ = nullptr;
   IntPoint drag_and_drop_autoscroll_reference_position_;
   TimeTicks drag_and_drop_autoscroll_start_time_;
-  IntPoint middle_click_autoscroll_start_pos_;
-  bool did_latch_for_middle_click_autoscroll_;
+
+  // Middle-click autoscroll.
+  FloatPoint middle_click_autoscroll_start_pos_global_;
+  FloatSize last_velocity_;
+  MiddleClickMode middle_click_mode_ = kMiddleClickInitial;
 };
 
 }  // namespace blink