Standardize usage of virtual/override/final in components/

components/crash/app/breakpad_mac.mm

 // Copyright 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.
 
 #import "components/crash/app/breakpad_mac.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #import <Foundation/Foundation.h>
 
 #include "base/auto_reset.h"
@@ skipping 98 matching lines @@
       // The entire point of this is to block so that the correct
       // stack is logged.
       base::ThreadRestrictions::ScopedAllowIO allow_io;
       base::PlatformThread::Join(handle);
     }
   }
 
  private:
   DumpHelper() {}
 
-  virtual void ThreadMain() override {
+  void ThreadMain() override {
     base::PlatformThread::SetName("CrDumpHelper");
     BreakpadGenerateAndSendReport(gBreakpadRef);
   }
 
   DISALLOW_COPY_AND_ASSIGN(DumpHelper);
 };
 
 void SIGABRTHandler(int signal) {
   // The OSX abort() (link below) masks all signals for the process,
   // and all except SIGABRT for the thread.  SIGABRT will be masked
@@ skipping 151 matching lines @@
 
   // Store process type in crash dump.
   SetCrashKeyValue(@"ptype", process_type);
 
   NSString* pid_value =
       [NSString stringWithFormat:@"%d", static_cast<unsigned int>(getpid())];
   SetCrashKeyValue(@"pid", pid_value);
 }
 
 }  // namespace breakpad