Set the correct buttons for long press action

third_party/WebKit/Source/core/input/EventHandler.cpp

Index: third_party/WebKit/Source/core/input/EventHandler.cpp
diff --git a/third_party/WebKit/Source/core/input/EventHandler.cpp b/third_party/WebKit/Source/core/input/EventHandler.cpp
index 038faa35d7cfaa1d7f062fe119ffeda61e22efb2..c8d25e5918bb9b8c6b6943a54dcc1ebb5bae4aeb 100644
--- a/third_party/WebKit/Source/core/input/EventHandler.cpp
+++ b/third_party/WebKit/Source/core/input/EventHandler.cpp
@@ -3038,7 +3038,7 @@ WebInputEventResult EventHandler::sendContextMenuEventForGesture(const GestureEv
         modifiers |= PlatformEvent::RightButtonDown;
 
     PlatformMouseEvent mouseEvent(targetedEvent.event().position(), targetedEvent.event().globalPosition(), RightButton, eventType, 1,
-        static_cast<PlatformEvent::Modifiers>(modifiers),
+        static_cast<PlatformEvent::Modifiers>(modifiers | PlatformEvent::RightButtonDown),
         PlatformMouseEvent::FromTouch, WTF::monotonicallyIncreasingTime(), WebPointerProperties::PointerType::Mouse);
     // To simulate right-click behavior, we send a right mouse down and then
     // context menu event.