Add use counter for dispatching mouse events on disabled form controls.

third_party/WebKit/Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  *
@@ skipping 70 matching lines @@
 #include "core/events/PointerEvent.h"
 #include "core/events/PointerEventFactory.h"
 #include "core/events/TextEvent.h"
 #include "core/events/TouchEvent.h"
 #include "core/events/UIEvent.h"
 #include "core/events/WheelEvent.h"
 #include "core/frame/EventHandlerRegistry.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/UseCounter.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/HTMLSlotElement.h"
 #include "core/input/EventHandler.h"
 #include "core/layout/LayoutBox.h"
 #include "core/page/ContextMenuController.h"
 #include "core/page/Page.h"
 #include "core/svg/SVGElement.h"
 #include "core/svg/graphics/SVGImage.h"
 #include "platform/EventDispatchForbiddenScope.h"
@@ skipping 1990 matching lines @@
       for (auto& registration : *transient_registry)
         registration->ObservedSubtreeNodeWillDetach(*this);
     }
   }
 }
 
 void Node::HandleLocalEvents(Event& event) {
   if (!HasEventTargetData())
     return;
 
-  if (IsDisabledFormControl(this) && event.IsMouseEvent())
+  if (IsDisabledFormControl(this) && event.IsMouseEvent()) {
+    UseCounter::Count(GetDocument(),
+                      UseCounter::kDispatchMouseEventOnDisabledFormControl);
     return;
+  }
 
   FireEventListeners(&event);
 }
 
 void Node::DispatchScopedEvent(Event* event) {
   event->SetTrusted(true);
   EventDispatcher::DispatchScopedEvent(*this, event->CreateMediator());
 }
 
 DispatchEventResult Node::DispatchEventInternal(Event* event) {
@@ skipping 450 matching lines @@
   if (node) {
     std::stringstream stream;
     node->PrintNodePathTo(stream);
     LOG(INFO) << stream.str();
   } else {
     LOG(INFO) << "Cannot showNodePath for <null>";
   }
 }
 
 #endif