Replace OVERRIDE->override and FINAL->final since we now require C++11.

src/snapshot/serialize.cc

Index: src/snapshot/serialize.cc
diff --git a/src/snapshot/serialize.cc b/src/snapshot/serialize.cc
index 3fbf5908e0e6f696eedb6fcd3503ecc44e33e8f4..b7c7dc1dd1c012264705860fd832e087910fc67e 100644
--- a/src/snapshot/serialize.cc
+++ b/src/snapshot/serialize.cc
@@ -676,7 +676,7 @@ class StringTableInsertionKey : public HashTableKey {
     DCHECK(string->IsInternalizedString());
   }
 
-  bool IsMatch(Object* string) OVERRIDE {
+  bool IsMatch(Object* string) override {
     // We know that all entries in a hash table had their hash keys created.
     // Use that knowledge to have fast failure.
     if (hash_ != HashForObject(string)) return false;
@@ -684,14 +684,13 @@ class StringTableInsertionKey : public HashTableKey {
     return string_->SlowEquals(String::cast(string));
   }
 
-  uint32_t Hash() OVERRIDE { return hash_; }
+  uint32_t Hash() override { return hash_; }
 
-  uint32_t HashForObject(Object* key) OVERRIDE {
+  uint32_t HashForObject(Object* key) override {
     return String::cast(key)->Hash();
   }
 
-  MUST_USE_RESULT virtual Handle<Object> AsHandle(Isolate* isolate)
-      OVERRIDE {
+  MUST_USE_RESULT virtual Handle<Object> AsHandle(Isolate* isolate) override {
     return handle(string_, isolate);
   }