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

third_party/tcmalloc/chromium/src/heap-profiler.cc

 // 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 419 matching lines @@
                   (uintptr_t) ptr, size);
 #ifdef TODO_REENABLE_STACK_TRACING
     DumpStackTrace(1, RawInfoStackDumper, NULL);
 #endif
   }
   if (saved_munmap_hook) {  // call MemoryRegionMap's hook
     (*saved_munmap_hook)(ptr, size);
   }
 }
 
-static void SbrkHook(const void* result, ptrdiff_t increment) {
+static void SbrkHook(const void* result, std::ptrdiff_t increment) {
   if (FLAGS_mmap_log) {  // log it
     RAW_LOG(INFO, "sbrk(inc=%"PRIdS") = 0x%"PRIxPTR"",
                   increment, (uintptr_t) result);
 #ifdef TODO_REENABLE_STACK_TRACING
     DumpStackTrace(1, RawInfoStackDumper, NULL);
 #endif
   }
   if (saved_sbrk_hook) {  // call MemoryRegionMap's hook
     (*saved_sbrk_hook)(result, increment);
   }
@@ skipping 161 matching lines @@
 
 // class used for finalization -- dumps the heap-profile at program exit
 struct HeapProfileEndWriter {
   ~HeapProfileEndWriter() { HeapProfilerDump("Exiting"); }
 };
 
 // We want to make sure tcmalloc is up and running before starting the profiler
 static const TCMallocGuard tcmalloc_initializer;
 REGISTER_MODULE_INITIALIZER(heapprofiler, HeapProfilerInit());
 static HeapProfileEndWriter heap_profile_end_writer;