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;

[bokan, 2016/08/12 15:29:17]

Is this a change in behaviour? It looks like we'd previously prevent sending the
click event on right clicks and now we send it.

[Navid Zolghadr, 2016/08/12 15:39:16]

That is correct. But not quite a change in the behavior. We were preventing
click event on right click (and left click when happens with control on Mac).
Now we send auxclick for right clicks. So we don't prevent that and we send
auxclick if right click happens.

[bokan, 2016/08/12 15:42:20]

Got it. But if RuntimeEnabledFeatures::auxclickEnabled is off, won't we now send
a click event?

[Navid Zolghadr, 2016/08/12 16:01:18]

Right. Thanks for the catch. I'm surprised why the output of the test in stable
didn't break in that case. Probably context menu opens and consumes the events
or something like that. But I fixed this contextMenuEvent to consider whether
auxclick is enabled or not and initialized it based on that.

 #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,
+                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