Drag and drop cleans up touch sequences from the source window.

ash/drag_drop/drag_drop_controller.cc

 // Copyright (c) 2012 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 "ash/drag_drop/drag_drop_controller.h"
 
 #include <utility>
 
 #include "ash/drag_drop/drag_drop_tracker.h"
 #include "ash/drag_drop/drag_image_view.h"
@@ skipping 155 matching lines @@
   UMA_HISTOGRAM_ENUMERATION("Event.DragDrop.Start", source,
                             ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
 
   current_drag_event_source_ = source;
   DragDropTracker* tracker =
       new DragDropTracker(root_window, drag_drop_window_delegate_.get());
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
     // We need to transfer the current gesture sequence and the GR's touch event
     // queue to the |drag_drop_tracker_|'s capture window so that when it takes
     // capture, it still gets a valid gesture state.
-    ui::GestureRecognizer::Get()->TransferEventsTo(source_window,
-        tracker->capture_window());
+    ui::GestureRecognizer::Get()->TransferEventsTo(
+        source_window, tracker->capture_window(),
+        ui::GestureRecognizer::ShouldCancelTouches::Cancel);
     // We also send a gesture end to the source window so it can clear state.
     // TODO(varunjain): Remove this whole block when gesture sequence
     // transferring is properly done in the GR (http://crbug.com/160558)
     DispatchGestureEndToWindow(source_window);
   }
   tracker->TakeCapture();
   drag_drop_tracker_.reset(tracker);
   drag_source_window_ = source_window;
   if (drag_source_window_)
     drag_source_window_->AddObserver(this);
@@ skipping 376 matching lines @@
   if (drag_window_)
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   // Cleanup can be called again while deleting DragDropTracker, so delete
   // the pointer with a local variable to avoid double free.
   std::unique_ptr<ash::DragDropTracker> holder = std::move(drag_drop_tracker_);
 }
 
 }  // namespace ash