Fix license headers in a number of files

third_party/tcmalloc/chromium/src/linux_shadow_stacks.cc

-// Copyright (c) 2006-2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
 #include "linux_shadow_stacks.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
@@ skipping 107 matching lines @@
 
 void *get_shadow_ip_stack(int *index /*OUT*/) {
   *index = shadow_index;
   return shadow_ip_stack;
 }
 
 void *get_shadow_sp_stack(int *index /*OUT*/) {
   *index = shadow_index;
   return shadow_sp_stack;
 }