Simplify the usage of singleton

chromium_src/chrome/browser/process_singleton_posix.cc

@@ -1046,4 +1046,4 @@ void ProcessSingleton::KillProcess(int pid) {
   // progress of shutting down and finishes before we try to kill it).
   DCHECK(rv == 0 || errno == ESRCH) << "Error killing process: "
                                     << base::safe_strerror(errno);
-}
+}

chromium_src/chrome/browser/process_singleton_startup_lock.cc

@@ -50,4 +50,4 @@ bool ProcessSingletonStartupLock::NotificationCallbackImpl(
   } else {
     return original_callback_.Run(command_line, current_directory);
   }
-}
+}

chromium_src/chrome/browser/process_singleton_startup_lock.h

@@ -54,4 +54,4 @@ class ProcessSingletonStartupLock : public base::NonThreadSafe {
   DISALLOW_COPY_AND_ASSIGN(ProcessSingletonStartupLock);
 };
 
-#endif  // CHROME_BROWSER_PROCESS_SINGLETON_STARTUP_LOCK_H_
+#endif  // CHROME_BROWSER_PROCESS_SINGLETON_STARTUP_LOCK_H_