Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/events/MouseEvent.cpp

Index: Source/core/events/MouseEvent.cpp
diff --git a/Source/core/events/MouseEvent.cpp b/Source/core/events/MouseEvent.cpp
index 8c3d2fac671ad8469a6dc9ed65837d85560e8ef8..cefef7ab332e66cdfd95bce01843dcc694632876 100644
--- a/Source/core/events/MouseEvent.cpp
+++ b/Source/core/events/MouseEvent.cpp
@@ -41,7 +41,7 @@ MouseEventInit::MouseEventInit()
     , shiftKey(false)
     , metaKey(false)
     , button(0)
-    , relatedTarget(0)
+    , relatedTarget(nullptr)
 {
 }
 
@@ -62,7 +62,7 @@ PassRefPtr<MouseEvent> MouseEvent::create(const AtomicString& eventType, PassRef
         detail, event.globalPosition().x(), event.globalPosition().y(), event.position().x(), event.position().y(),
         event.movementDelta().x(), event.movementDelta().y(),
         event.ctrlKey(), event.altKey(), event.shiftKey(), event.metaKey(), event.button(),
-        relatedTarget, 0, false);
+        relatedTarget, nullptr, false);
 }
 
 PassRefPtr<MouseEvent> MouseEvent::create(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<AbstractView> view,
@@ -110,7 +110,7 @@ MouseEvent::MouseEvent(const AtomicString& eventType, const MouseEventInit& init
     , m_button(initializer.button == (unsigned short)-1 ? 0 : initializer.button)
     , m_buttonDown(initializer.button != (unsigned short)-1)
     , m_relatedTarget(initializer.relatedTarget)
-    , m_clipboard(0 /* clipboard */)
+    , m_clipboard(nullptr /* clipboard */)
 {
     ScriptWrappable::init(this);
     initCoordinates(IntPoint(initializer.clientX, initializer.clientY));
@@ -202,7 +202,7 @@ SimulatedMouseEvent::~SimulatedMouseEvent()
 SimulatedMouseEvent::SimulatedMouseEvent(const AtomicString& eventType, PassRefPtr<AbstractView> view, PassRefPtr<Event> underlyingEvent)
     : MouseEvent(eventType, true, true, view, 0, 0, 0, 0, 0,
                  0, 0,
-                 false, false, false, false, 0, 0, 0, true)
+                 false, false, false, false, 0, nullptr, nullptr, true)
 {
     if (UIEventWithKeyState* keyStateEvent = findEventWithKeyState(underlyingEvent.get())) {
         m_ctrlKey = keyStateEvent->ctrlKey();