exo: Replace fling cancel with generic zero distance scroll

components/exo/pointer.cc

 // Copyright 2015 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.
 
 #include "components/exo/pointer.h"
 
 #include "ash/display/display_manager.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "components/exo/pointer_delegate.h"
 #include "components/exo/pointer_stylus_delegate.h"
@@ skipping 229 matching lines @@
         delegate_->OnPointerFrame();
       }
       break;
     case ui::ET_SCROLL_FLING_START:
       if (focus_) {
         delegate_->OnPointerScrollStop(event->time_stamp());
         delegate_->OnPointerFrame();
       }
       break;
     case ui::ET_SCROLL_FLING_CANCEL:
-      if (focus_) {
-        delegate_->OnPointerScrollCancel(event->time_stamp());

[reveman, 2016/10/31 02:25:12]

can we remove OnPointerScrollCancel from the delegate interface?

[denniskempin, 2016/10/31 17:33:48]

Done.

+      if (focus_ && last_event_type_ == ui::ET_SCROLL_FLING_START) {
+        delegate_->OnPointerScroll(event->time_stamp(), gfx::Vector2dF(),
+                                   false);
+        delegate_->OnPointerFrame();
+        delegate_->OnPointerScrollStop(event->time_stamp());
         delegate_->OnPointerFrame();
       }
       break;
     case ui::ET_MOUSE_MOVED:
     case ui::ET_MOUSE_DRAGGED:
     case ui::ET_MOUSE_ENTERED:
     case ui::ET_MOUSE_EXITED:
     case ui::ET_MOUSE_CAPTURE_CHANGED:
       break;
     default:
@@ skipping 17 matching lines @@
       widget_->SetBounds(bounds);
     }
 
     UpdateCursorScale();
     if (!widget_->IsVisible())
       widget_->Show();
   } else {
     if (widget_ && widget_->IsVisible())
       widget_->Hide();
   }
+
+  if ((event->flags() & ui::EF_IS_SYNTHESIZED) == 0)

[reveman, 2016/10/31 02:25:12]

can we merge this with the "event->flags() & ui::EF_IS_SYNTHESIZED" if statement
above?

[denniskempin, 2016/10/31 17:33:49]

Done.

+    last_event_type_ = event->type();
 }
 
 void Pointer::OnScrollEvent(ui::ScrollEvent* event) {
   OnMouseEvent(event);
 }
 
 void Pointer::OnCursorSetChanged(ui::CursorSetType cursor_set) {
   UpdateCursorScale();
 }
 
@@ skipping 70 matching lines @@
 
   if (ui_scale != cursor_scale_) {
     gfx::Transform transform;
     transform.Scale(ui_scale, ui_scale);
     widget_->GetNativeWindow()->SetTransform(transform);
     cursor_scale_ = ui_scale;
   }
 }
 
 }  // namespace exo