Convert OVERRIDE -> override and update virtual/final usage in tools/gn/.

tools/gn/scope_per_file_provider.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_GN_SCOPE_PER_FILE_PROVIDER_H_
 #define TOOLS_GN_SCOPE_PER_FILE_PROVIDER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/source_file.h"
 
 // ProgrammaticProvider for a scope to provide it with per-file built-in
 // variable support.
 class ScopePerFileProvider : public Scope::ProgrammaticProvider {
  public:
   // allow_target_vars allows the target-related variables to get resolved.
   // When allow_target_vars is unset, the target-related values will be
   // undefined to GN script.
   ScopePerFileProvider(Scope* scope, bool allow_target_vars);
   virtual ~ScopePerFileProvider();
 
   // ProgrammaticProvider implementation.
-  virtual const Value* GetProgrammaticValue(
-      const base::StringPiece& ident) override;
+  const Value* GetProgrammaticValue(const base::StringPiece& ident) override;
 
  private:
   const Value* GetCurrentToolchain();
   const Value* GetDefaultToolchain();
   const Value* GetPythonPath();
   const Value* GetRootBuildDir();
   const Value* GetRootGenDir();
   const Value* GetRootOutDir();
   const Value* GetTargetGenDir();
   const Value* GetTargetOutDir();
 
   bool allow_target_vars_;
 
   // All values are lazily created.
   scoped_ptr<Value> current_toolchain_;
   scoped_ptr<Value> default_toolchain_;
   scoped_ptr<Value> python_path_;
   scoped_ptr<Value> root_build_dir_;
   scoped_ptr<Value> root_gen_dir_;
   scoped_ptr<Value> root_out_dir_;
   scoped_ptr<Value> target_gen_dir_;
   scoped_ptr<Value> target_out_dir_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopePerFileProvider);
 };
 
 #endif  // TOOLS_GN_SCOPE_PER_FILE_PROVIDER_H_