Landing http://codereview.chromium.org/7033062/:

third_party/tcmalloc/chromium/src/base/vdso_support.cc

 // Copyright (c) 2008, Google Inc.
 // All rights reserved.
 // 
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 // 
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 243 matching lines @@
         break;
     }
   }
   if (link_base_ == ~0L || !dynamic_program_header) {
     RAW_DCHECK(~0L != link_base_, "no PT_LOADs in VDSO");
     RAW_DCHECK(dynamic_program_header, "no PT_DYNAMIC in VDSO");
     // Mark this image as not present. Can not recur infinitely.
     Init(0);
     return;
   }
-  ptrdiff_t relocation =
+  std::ptrdiff_t relocation =
       base_as_char - reinterpret_cast<const char *>(link_base_);
   ElfW(Dyn) *dynamic_entry =
       reinterpret_cast<ElfW(Dyn) *>(dynamic_program_header->p_vaddr +
                                     relocation);
   bool fake_vdso = false;  // Assume we are dealing with the real VDSO.
   for (ElfW(Dyn) *de = dynamic_entry; de->d_tag != DT_NULL; ++de) {
     ElfW(Sxword) tag = de->d_tag;
     if (tag == DT_PLTGOT || tag == DT_RELA || tag == DT_JMPREL ||
         tag == DT_NEEDED || tag == DT_RPATH || tag == DT_VERNEED ||
         tag == DT_INIT || tag == DT_FINI) {
@@ skipping 285 matching lines @@
 // ensure it here, with a global constructor of our own.  This
 // is an allowed exception to the normal rule against non-trivial
 // global constructors.
 static class VDSOInitHelper {
  public:
   VDSOInitHelper() { VDSOSupport::Init(); }
 } vdso_init_helper;
 }
 
 #endif  // HAVE_VDSO_SUPPORT