Identify context menus being opened via the long press gesture

content/renderer/input/render_widget_input_handler.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 "content/renderer/input/render_widget_input_handler.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <utility>
 
@@ skipping 276 matching lines @@
         widget_->GetTextInputType() != ui::TEXT_INPUT_TYPE_NONE) {
       widget_->showImeIfNeeded();
       prevent_default = true;
     }
 #endif
   }
 
   if (WebInputEvent::isGestureEventType(input_event.type)) {
     const WebGestureEvent& gesture_event =
         static_cast<const WebGestureEvent&>(input_event);
-    context_menu_source_type_ = ui::MENU_SOURCE_TOUCH;
+    context_menu_source_type_ =
+        ((input_event.type == WebInputEvent::GestureLongPress) ?
+              ui::MENU_SOURCE_LONG_PRESS : ui::MENU_SOURCE_TOUCH);
     prevent_default =
         prevent_default || delegate_->WillHandleGestureEvent(gesture_event);
   }
 
   WebInputEventResult processed = prevent_default
                                       ? WebInputEventResult::HandledSuppressed
                                       : WebInputEventResult::NotHandled;
   if (input_event.type != WebInputEvent::Char || !suppress_next_char_events_) {
     suppress_next_char_events_ = false;
     if (processed == WebInputEventResult::NotHandled && widget_->webwidget())
@@ skipping 198 matching lines @@
   if (pending_input_event_ack_) {
     TRACE_EVENT_ASYNC_END0("input",
                            "RenderWidgetInputHandler::ThrottledInputEventAck",
                            pending_input_event_ack_.get());
     delegate_->OnInputEventAck(std::move(pending_input_event_ack_));
   }
   total_input_handling_time_this_frame_ = base::TimeDelta();
 }
 
 }  // namespace content