[wasm] s/NULL/nullptr/g

src/wasm/encoder.h

Index: src/wasm/encoder.h
diff --git a/src/wasm/encoder.h b/src/wasm/encoder.h
index 2a73deea9eabbad1e60a8f5306a7750ad2c3cf3e..ba72ae1d9b90ce842e7dae995252f53ec831d36d 100644
--- a/src/wasm/encoder.h
+++ b/src/wasm/encoder.h
@@ -125,7 +125,8 @@ class WasmModuleWriter : public ZoneObject {
 class WasmModuleBuilder : public ZoneObject {
  public:
   explicit WasmModuleBuilder(Zone* zone);
-  uint16_t AddFunction(const unsigned char* name = NULL, int name_length = 0);
+  uint16_t AddFunction(const unsigned char* name = nullptr,
+                       int name_length = 0);
   uint32_t AddGlobal(MachineType type, bool exported);
   WasmFunctionBuilder* FunctionAt(size_t index);
   void AddDataSegment(WasmDataSegmentEncoder* data);