ozone/wayland: tabdrag: Do not assume mouse as the drag source

Do not dcheck for mouse button state when processing the drop event as
it causes crashes in lacros when the tab drag session is triggered by
touch events.

Upcoming CLs will add actual support for touch-based tab drag sessions.

R=msisov@igalia.com

Bug: 1158557
Change-Id: Ic68a076934dbe669fb713d4a4f9ce9a02d008e91
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2594021Reviewed-by: Maksim Sisov (slow) <msisov@igalia.com>
Commit-Queue: Nick Yamane <nickdiego@igalia.com>
Auto-Submit: Nick Yamane <nickdiego@igalia.com>
Cr-Commit-Position: refs/heads/master@{#837489}

ui/ozone/platform/wayland/host/wayland_window_drag_controller.cc

@@ -36,7 +36,6 @@
 #include "ui/ozone/platform/wayland/host/wayland_data_device_manager.h"
 #include "ui/ozone/platform/wayland/host/wayland_data_offer.h"
 #include "ui/ozone/platform/wayland/host/wayland_data_source.h"
-#include "ui/ozone/platform/wayland/host/wayland_event_source.h"
 #include "ui/ozone/platform/wayland/host/wayland_pointer.h"
 #include "ui/ozone/platform/wayland/host/wayland_surface.h"
 #include "ui/ozone/platform/wayland/host/wayland_window.h"
@@ -395,7 +394,6 @@ void WaylandWindowDragController::HandleDropAndResetState() {
   VLOG(1) << "Notifying drop. window=" << pointer_grab_owner_;
 
   EventFlags pointer_button = EF_LEFT_MOUSE_BUTTON;
-  DCHECK(connection_->event_source()->IsPointerButtonPressed(pointer_button));
   pointer_delegate_->OnPointerButtonEvent(ET_MOUSE_RELEASED, pointer_button,
                                           pointer_grab_owner_);