Hook up allocator shim on mac.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 69dfcc5b3bbe28700b259a9ad2e2decec8e70b4c..2b901879cbb2509d8de6fa388a9e6282e93c4e9b 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -1144,6 +1144,12 @@ component("base") {
         "allocator/allocator_shim_override_linker_wrapped_symbols.h",
       ]
       all_dependent_configs += [ "//base/allocator:wrap_malloc_symbols" ]
+    } else if (is_mac) {
+      sources += [
+        "allocator/allocator_shim_default_dispatch_to_zoned_malloc.cc",

[Primiano Tucci (use gerrit), 2017/01/28 05:10:02]

since this is mac only, can those two files have "mac" in their name? will make
it easier to make a sense out of the base/Allocator directory. proposals:

allocator_shim_default_dispatch_to_mac_zoned_malloc.{cc,h}
allocator_shim_default_dispatch_to_mac_malloc.{cc,h}
allocator_shim_default_dispatch_to_mac_system_allocator.{cc,h}
or anything else with "mac" in the name 

[erikchen, 2017/01/31 02:21:22]

Done.

+        "allocator/allocator_shim_default_dispatch_to_zoned_malloc.h",
+        "allocator/allocator_shim_override_mac_symbols.h",
+      ]
     }
   }