Reland "Use V8_FINAL and V8_OVERRIDE in various places, fixing bugs revealed by them.".

src/x64/lithium-codegen-x64.h

Index: src/x64/lithium-codegen-x64.h
diff --git a/src/x64/lithium-codegen-x64.h b/src/x64/lithium-codegen-x64.h
index a74ec7982c4c624b16568a6b7483ffc42f74af70..65c6dcae1f9793c6e668c03bc894a1115e2e3f56 100644
--- a/src/x64/lithium-codegen-x64.h
+++ b/src/x64/lithium-codegen-x64.h
@@ -44,7 +44,7 @@ namespace internal {
 class LDeferredCode;
 class SafepointGenerator;
 
-class LCodeGen BASE_EMBEDDED {
+class LCodeGen V8_FINAL BASE_EMBEDDED {
  public:
   LCodeGen(LChunk* chunk, MacroAssembler* assembler, CompilationInfo* info)
       : zone_(info->zone()),
@@ -384,7 +384,7 @@ class LCodeGen BASE_EMBEDDED {
 
   int old_position_;
 
-  class PushSafepointRegistersScope BASE_EMBEDDED {
+  class PushSafepointRegistersScope V8_FINAL BASE_EMBEDDED {
    public:
     explicit PushSafepointRegistersScope(LCodeGen* codegen)
         : codegen_(codegen) {
@@ -420,7 +420,7 @@ class LDeferredCode: public ZoneObject {
     codegen->AddDeferredCode(this);
   }
 
-  virtual ~LDeferredCode() { }
+  virtual ~LDeferredCode() {}
   virtual void Generate() = 0;
   virtual LInstruction* instr() = 0;