Refactoring button field and its type

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

Index: third_party/WebKit/Source/core/input/PointerEventManager.cpp
diff --git a/third_party/WebKit/Source/core/input/PointerEventManager.cpp b/third_party/WebKit/Source/core/input/PointerEventManager.cpp
index d258c2e85bba0711c5c58fad918864911fb5ecfa..d6d09a42fbc9600e38c306ffd99c946dc606bf9e 100644
--- a/third_party/WebKit/Source/core/input/PointerEventManager.cpp
+++ b/third_party/WebKit/Source/core/input/PointerEventManager.cpp
@@ -184,7 +184,7 @@ void PointerEventManager::sendMouseAndPossiblyPointerBoundaryEvents(
     // |sendBoundaryEvents| function.
     PointerEvent* dummyPointerEvent =
         m_pointerEventFactory.create(EventTypeNames::mousedown, mouseEvent,
-        nullptr, m_frame->document()->domWindow());
+        m_frame->document()->domWindow());
 
     // TODO(crbug/545647): This state should reset with pointercancel too.
     // This function also gets called for compat mouse events of touch at this
@@ -518,13 +518,12 @@ WebInputEventResult PointerEventManager::sendTouchPointerEvent(
 WebInputEventResult PointerEventManager::sendMousePointerEvent(
     Node* target, const AtomicString& mouseEventType,
     int clickCount, const PlatformMouseEvent& mouseEvent,
-    Node* relatedTarget,
     Node* lastNodeUnderMouse,
     Node** newNodeUnderMouse)
 {
     PointerEvent* pointerEvent =
         m_pointerEventFactory.create(mouseEventType, mouseEvent,
-        relatedTarget, m_frame->document()->domWindow());
+        m_frame->document()->domWindow());
 
     // This is for when the mouse is released outside of the page.
     if (pointerEvent->type() == EventTypeNames::pointermove