Correctly name header macros for src/snapshot/*.h.

src/snapshot/serialize.h

Index: src/snapshot/serialize.h
diff --git a/src/snapshot/serialize.h b/src/snapshot/serialize.h
index bb33cf77383a401787143e79e55c094fcb9f99d5..f8b6c4cea06dbe0f64356beca92b31f7b5a4f831 100644
--- a/src/snapshot/serialize.h
+++ b/src/snapshot/serialize.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef V8_SERIALIZE_H_
-#define V8_SERIALIZE_H_
+#ifndef V8_SNAPSHOT_SERIALIZE_H_
+#define V8_SNAPSHOT_SERIALIZE_H_
 
 #include "src/hashmap.h"
 #include "src/heap-profiler.h"
@@ -1001,4 +1001,4 @@ class SerializedCodeData : public SerializedData {
 };
 } }  // namespace v8::internal
 
-#endif  // V8_SERIALIZE_H_
+#endif  // V8_SNAPSHOT_SERIALIZE_H_