Suppress mouseup/down when button is NoButton

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 959 matching lines @@
     FrameView* view = frame->view();
     // FIXME: Is it really OK to use the wrong coordinates here when view is 0?
     // Historically the code would just crash; this is clearly no worse than that.
     return view ? view->rootFrameToContents(pointInRootFrame) : pointInRootFrame;
 }
 
 WebInputEventResult EventHandler::handleMousePressEvent(const PlatformMouseEvent& mouseEvent)
 {
     TRACE_EVENT0("blink", "EventHandler::handleMousePressEvent");
 
+    // For 4th/5th button in the mouse since Chrome does not yet send
+    // button value to Blink but in some cases it does send the event.
+    // This check is needed to suppress such an event (crbug.com/574959)
+    if (mouseEvent.button() == NoButton)
+        return WebInputEventResult::HandledSuppressed;
+
     RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
 
     UserGestureIndicator gestureIndicator(DefinitelyProcessingUserGesture);
     m_frame->localFrameRoot()->eventHandler().m_lastMouseDownUserGestureToken = gestureIndicator.currentToken();
 
     cancelFakeMouseMoveEvent();
     if (m_eventHandlerWillResetCapturingMouseEventsNode)
         m_capturingMouseEventsNode = nullptr;
     m_mousePressed = true;
     m_capturesDragging = true;
@@ skipping 308 matching lines @@
     if (node.isHTMLElement() && toHTMLElement(node).isInteractiveContent())
         return nullptr;
 
     return FlatTreeTraversal::parent(node);
 }
 
 WebInputEventResult EventHandler::handleMouseReleaseEvent(const PlatformMouseEvent& mouseEvent)
 {
     TRACE_EVENT0("blink", "EventHandler::handleMouseReleaseEvent");
 
+    // For 4th/5th button in the mouse since Chrome does not yet send
+    // button value to Blink but in some cases it does send the event.
+    // This check is needed to suppress such an event (crbug.com/574959)
+    if (mouseEvent.button() == NoButton)
+        return WebInputEventResult::HandledSuppressed;
+
     RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
 
     m_frame->selection().setCaretBlinkingSuspended(false);
 
     OwnPtr<UserGestureIndicator> gestureIndicator;
 
     if (m_frame->localFrameRoot()->eventHandler().m_lastMouseDownUserGestureToken)
         gestureIndicator = adoptPtr(new UserGestureIndicator(m_frame->localFrameRoot()->eventHandler().m_lastMouseDownUserGestureToken.release()));
     else
         gestureIndicator = adoptPtr(new UserGestureIndicator(DefinitelyProcessingUserGesture));
@@ skipping 2655 matching lines @@
 PlatformEvent::Modifiers EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return static_cast<PlatformEvent::Modifiers>(PlatformEvent::CtrlKey | PlatformEvent::AltKey);
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink