Revive malloc_hook_mmap_linux.h in Android.

third_party/tcmalloc/chromium/src/malloc_hook.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 676 matching lines @@
     // e.g. for every section used in InHookCaller
     // all functions in that section must be inside the same library.
   return 0;
 #endif
 }
 
 // On systems where we know how, we override mmap/munmap/mremap/sbrk
 // to provide support for calling the related hooks (in addition,
 // of course, to doing what these functions normally do).
 
-#if defined(__linux) && !defined(__ANDROID__)
+#if defined(__linux)
 # include "malloc_hook_mmap_linux.h"
 
 #elif defined(__FreeBSD__)
 # include "malloc_hook_mmap_freebsd.h"
 
 #else
 
 /*static*/void* MallocHook::UnhookedMMap(void *start, size_t length, int prot,
                                          int flags, int fd, off_t offset) {
   void* result;
   if (!MallocHook::InvokeMmapReplacement(
           start, length, prot, flags, fd, offset, &result)) {
     result = mmap(start, length, prot, flags, fd, offset);
   }
   return result;
 }
 
 /*static*/int MallocHook::UnhookedMUnmap(void *start, size_t length) {
   int result;
   if (!MallocHook::InvokeMunmapReplacement(start, length, &result)) {
     result = munmap(start, length);
   }
   return result;
 }
 
 #endif