Start sending auxclick instead of click for non-primary buttons

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 1132 matching lines @@
     HitTestRequest request(hitType);
     MouseEventWithHitTestResults mev = prepareMouseEvent(request, mouseEvent);
     LocalFrame* subframe = m_capturingMouseEventsNode.get() ? subframeForTargetNode(m_capturingMouseEventsNode.get()) : subframeForHitTestResult(mev);
     if (m_eventHandlerWillResetCapturingMouseEventsNode)
         m_capturingMouseEventsNode = nullptr;
     if (subframe)
         return passMouseReleaseEventToSubframe(mev, subframe);
 
     WebInputEventResult eventResult = updatePointerTargetAndDispatchEvents(EventTypeNames::mouseup, mev.innerNode(), m_clickCount, mev.event());
 
-    bool contextMenuEvent = mouseEvent.button() == RightButton;
+    // We only prevent click event when the click may cause contextmenu to popup.
+    // However, we always send auxclick.
+    bool macContextMenuEvent = false;
 #if OS(MACOSX)
     // FIXME: The Mac port achieves the same behavior by checking whether the context menu is currently open in WebPage::mouseEvent(). Consider merging the implementations.
     if (mouseEvent.button() == LeftButton && mouseEvent.getModifiers() & PlatformEvent::CtrlKey)
-        contextMenuEvent = true;
+        macContextMenuEvent = true;
 #endif
 
     WebInputEventResult clickEventResult = WebInputEventResult::NotHandled;
     const bool shouldDispatchClickEvent = m_clickCount > 0
-        && !contextMenuEvent
+        && !macContextMenuEvent
         && mev.innerNode() && m_clickNode
         && mev.innerNode()->canParticipateInFlatTree() && m_clickNode->canParticipateInFlatTree()
         && !(selectionController().hasExtendedSelection() && isLinkSelection(mev));
     if (shouldDispatchClickEvent) {
         Node* clickTargetNode = nullptr;
         // Updates distribution because a 'mouseup' event listener can make the
         // tree dirty at dispatchMouseEvent() invocation above.
         // Unless distribution is updated, commonAncestor would hit ASSERT.
         if (m_clickNode == mev.innerNode()) {
             clickTargetNode = m_clickNode;
             clickTargetNode->updateDistribution();
         } else if (m_clickNode->document() == mev.innerNode()->document()) {
             m_clickNode->updateDistribution();
             mev.innerNode()->updateDistribution();
             clickTargetNode = mev.innerNode()->commonAncestor(
                 *m_clickNode, parentForClickEvent);
         }
         if (clickTargetNode) {
             // Dispatch mouseup directly w/o calling updateMouseEventTargetNodeAndSendEvents
             // because the mouseup dispatch above has already updated it
             // correctly. Moreover, clickTargetNode is different from
             // mev.innerNode at drag-release.
             clickEventResult = toWebInputEventResult(clickTargetNode->dispatchMouseEvent(mev.event(),
-                EventTypeNames::click, m_clickCount));
+                !RuntimeEnabledFeatures::auxclickEnabled() || (mev.event().button() == MouseButton::LeftButton)
+                    ? EventTypeNames::click
+                    : EventTypeNames::auxclick,

[Dan Beam, 2016/08/09 02:04:34]

so this guarantees there'll always be either 'click' with button == 1 OR an
'auxclick'?

[Navid Zolghadr, 2016/08/09 13:34:46]

That is correct. After this change for the primary button (which is Left mouse
button for example with enum value 0) we send click event and for all other
buttons we send auxclick. These events will have the exact same properties and
everything. So the previous js codes should just work listening to auxclick
instead of click or listening to both if they want.

+                m_clickCount));
         }
     }
 
     m_scrollManager.clearResizeScrollableArea(false);
 
     if (eventResult == WebInputEventResult::NotHandled)
         eventResult = handleMouseReleaseEvent(mev);
     clearDragHeuristicState();
 
     invalidateClick();
@@ skipping 1384 matching lines @@
 
 FrameHost* EventHandler::frameHost() const
 {
     if (!m_frame->page())
         return nullptr;
 
     return &m_frame->page()->frameHost();
 }
 
 } // namespace blink