Get rid of NULLs in fpdfsdk/

Review-Url: https://codereview.chromium.org/2031653003
diff --git a/fpdfsdk/javascript/Icon.cpp b/fpdfsdk/javascript/Icon.cpp
index 7dde8bf..031ec4f 100644
--- a/fpdfsdk/javascript/Icon.cpp
+++ b/fpdfsdk/javascript/Icon.cpp
@@ -23,7 +23,7 @@
 IMPLEMENT_JS_CLASS(CJS_Icon, Icon)
 
 Icon::Icon(CJS_Object* pJSObject)
-    : CJS_EmbedObj(pJSObject), m_pIconStream(NULL), m_swIconName(L"") {}
+    : CJS_EmbedObj(pJSObject), m_pIconStream(nullptr), m_swIconName(L"") {}
 
 Icon::~Icon() {}