Selection Action mode triggered like a context menu

third_party/WebKit/Source/core/events/MouseEvent.cpp

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 158 matching lines @@
           abstract_view
               ? abstract_view->GetInputDeviceCapabilities()->FiresTouchEvents(
                     event.FromTouch())
               : nullptr),
       screen_location_(event.PositionInScreen().x, event.PositionInScreen().y),
       movement_delta_(FlooredIntPoint(event.MovementInRootFrame())),
       position_type_(PositionType::kPosition),
       button_(static_cast<short>(event.button)),
       buttons_(WebInputEventModifiersToButtons(event.GetModifiers())),
       related_target_(related_target),
-      synthetic_event_type_(event.FromTouch() ? kFromTouch
-                                              : kRealOrIndistinguishable),
       region_(region) {
   IntPoint root_frame_coordinates =
       FlooredIntPoint(event.PositionInRootFrame());
   InitCoordinatesFromRootFrame(root_frame_coordinates.X(),
                                root_frame_coordinates.Y());
+  if (event.GetModifiers() & WebInputEvent::kSelectAll)
+    synthetic_event_type_ = kFromSelectAll;
+  else if (event.FromTouch())
+    synthetic_event_type_ = kFromTouch;
+  else
+    synthetic_event_type_ = kRealOrIndistinguishable;
 }
 
 MouseEvent::MouseEvent(const AtomicString& event_type,
                        bool can_bubble,
                        bool cancelable,
                        AbstractView* abstract_view,
                        int detail,
                        int screen_x,
                        int screen_y,
                        int window_x,
@@ skipping 402 matching lines @@
 
 int MouseEvent::offsetY() {
   if (!HasPosition())
     return 0;
   if (!has_cached_relative_position_)
     ComputeRelativePosition();
   return std::round(offset_location_.Y());
 }
 
 }  // namespace blink