Move middle-click autoscroll to synthetic fling.

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 664 matching lines @@
   bool event_cancelled = false;  // for disambiguation
 
   // Special handling for slow-path fling gestures.
   switch (event.GetType()) {
     case WebInputEvent::kGestureFlingStart: {
       if (MainFrameImpl()
               ->GetFrame()
               ->GetEventHandler()
               .IsScrollbarHandlingGestures())
         break;
-      EndActiveFlingAnimation();
+      if (event.source_device != kWebGestureDeviceSyntheticAutoscroll)
+        EndActiveFlingAnimation();
       position_on_fling_start_ = WebPoint(event.x, event.y);
       global_position_on_fling_start_ =
           WebPoint(event.global_x, event.global_y);
       fling_modifier_ = event.GetModifiers();
       fling_source_device_ = event.source_device;
       DCHECK_NE(fling_source_device_, kWebGestureDeviceUninitialized);
       std::unique_ptr<WebGestureCurve> fling_curve =
           Platform::Current()->CreateFlingAnimationCurve(
               event.source_device,
               WebFloatPoint(event.data.fling_start.velocity_x,
@@ skipping 1280 matching lines @@
 
   // Create synthetic wheel events as necessary for fling.
   if (gesture_animation_) {
     if (gesture_animation_->Animate(last_frame_time_monotonic))
       MainFrameImpl()->FrameWidget()->ScheduleAnimation();
     else {
       DCHECK_NE(fling_source_device_, kWebGestureDeviceUninitialized);
       WebGestureDevice last_fling_source_device = fling_source_device_;
       EndActiveFlingAnimation();
 
-      WebGestureEvent end_scroll_event = CreateGestureScrollEventFromFling(
-          WebInputEvent::kGestureScrollEnd, last_fling_source_device);
-      MainFrameImpl()->GetFrame()->GetEventHandler().HandleGestureScrollEnd(
-          end_scroll_event);
+      if (last_fling_source_device != kWebGestureDeviceSyntheticAutoscroll) {
+        WebGestureEvent end_scroll_event = CreateGestureScrollEventFromFling(
+            WebInputEvent::kGestureScrollEnd, last_fling_source_device);
+        MainFrameImpl()->GetFrame()->GetEventHandler().HandleGestureScrollEnd(
+            end_scroll_event);
+      }
     }
   }
 
   if (!MainFrameImpl())
     return;
 
   last_frame_time_monotonic_ = last_frame_time_monotonic;
 
   DocumentLifecycle::AllowThrottlingScope throttling_scope(
       MainFrameImpl()->GetFrame()->GetDocument()->Lifecycle());
@@ skipping 2119 matching lines @@
   if (focused_frame->LocalFrameRoot() != MainFrameImpl()->GetFrame())
     return nullptr;
   return focused_frame;
 }
 
 LocalFrame* WebViewImpl::FocusedLocalFrameAvailableForIme() const {
   return ime_accept_events_ ? FocusedLocalFrameInWidget() : nullptr;
 }
 
 }  // namespace blink