mac: Hook up allocator shim.

base/process/memory.cc

Index: base/process/memory.cc
diff --git a/base/process/memory.cc b/base/process/memory.cc
index 6349c08ca0a78643753564943b15509717cb303a..297410851f82b1f2641c72c38fdfee81563a07ad 100644
--- a/base/process/memory.cc
+++ b/base/process/memory.cc
@@ -30,9 +30,6 @@ void TerminateBecauseOutOfMemory(size_t size) {
 
 #endif
 
-// Defined in memory_mac.mm for Mac.
-#if !defined(OS_MACOSX)
-
 bool UncheckedCalloc(size_t num_items, size_t size, void** result) {
   const size_t alloc_size = num_items * size;
 
@@ -49,6 +46,4 @@ bool UncheckedCalloc(size_t num_items, size_t size, void** result) {
   return true;
 }
 
-#endif
-
 }  // namespace base