Replaced ptrdiff_t with std::ptrdiff_t in all files to enable build with gcc-4.6.0.

third_party/tcmalloc/chromium/src/malloc_hook-inl.h

 // Copyright (c) 2005, 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 152 matching lines @@
   MallocHook::MremapHook hook = MallocHook::GetMremapHook();
   if (hook != NULL) (*hook)(result,
                             old_addr, old_size,
                             new_size, flags, new_addr);
 }
 
 inline MallocHook::PreSbrkHook MallocHook::GetPreSbrkHook() {
   return base::internal::presbrk_hook_.Get();
 }
 
-inline void MallocHook::InvokePreSbrkHook(ptrdiff_t increment) {
+inline void MallocHook::InvokePreSbrkHook(std::ptrdiff_t increment) {
   MallocHook::PreSbrkHook hook = MallocHook::GetPreSbrkHook();
   if (hook != NULL && increment != 0) (*hook)(increment);
 }
 
 inline MallocHook::SbrkHook MallocHook::GetSbrkHook() {
   return base::internal::sbrk_hook_.Get();
 }
 
 inline void MallocHook::InvokeSbrkHook(const void* result,
-                                       ptrdiff_t increment) {
+                                       std::ptrdiff_t increment) {
   MallocHook::SbrkHook hook = MallocHook::GetSbrkHook();
   if (hook != NULL && increment != 0) (*hook)(result, increment);
 }
 
 #endif /* _MALLOC_HOOK_INL_H_ */