Start sending auxclick instead of click for non-primary buttons

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 cc58b44a8e10ad145b64a0c1093cc3dbf17af8be..adecd14afcf1ef8c51a06491bb4f611721f370ee 100644
--- a/third_party/WebKit/Source/core/input/EventHandler.cpp
+++ b/third_party/WebKit/Source/core/input/EventHandler.cpp
@@ -1155,16 +1155,18 @@ WebInputEventResult EventHandler::handleMouseReleaseEvent(const PlatformMouseEve
 
     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));
@@ -1188,7 +1190,10 @@ WebInputEventResult EventHandler::handleMouseReleaseEvent(const PlatformMouseEve
             // 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));
         }
     }