Make core/editing/ files to match Blink coding style

Source/core/editing/SmartReplaceCF.cpp

Index: Source/core/editing/SmartReplaceCF.cpp
diff --git a/Source/core/editing/SmartReplaceCF.cpp b/Source/core/editing/SmartReplaceCF.cpp
index 47aa7870a71316b55d27bb341cbd9078b40c6bd1..0a0719e14366ca97a11f3881594429cd0f1d9f6a 100644
--- a/Source/core/editing/SmartReplaceCF.cpp
+++ b/Source/core/editing/SmartReplaceCF.cpp
@@ -36,8 +36,8 @@ namespace blink {
 
 static CFMutableCharacterSetRef getSmartSet(bool isPreviousCharacter)
 {
-    static CFMutableCharacterSetRef preSmartSet = NULL;
-    static CFMutableCharacterSetRef postSmartSet = NULL;
+    static CFMutableCharacterSetRef preSmartSet = nullptr;
+    static CFMutableCharacterSetRef postSmartSet = nullptr;
     CFMutableCharacterSetRef smartSet = isPreviousCharacter ? preSmartSet : postSmartSet;
     if (!smartSet) {
         smartSet = CFCharacterSetCreateMutable(kCFAllocatorDefault);