Update Google Chrome Mac reference build.

DEPS

 vars = {
   # Use this googlecode_url variable only if there is an internal mirror for it.
   # If you do not know, use the full path while defining your new deps entry.
   "googlecode_url": "http://%s.googlecode.com/svn",
   "webkit_trunk": "http://svn.webkit.org/repository/webkit/trunk",
   "nacl_trunk": "http://src.chromium.org/native_client/trunk",
   "webkit_revision": "75393",
   "skia_revision": "673",
   "chromium_git": "http://git.chromium.org/git",
   "swig_revision": "69281",
@@ skipping 218 matching lines @@
 
     "src/rlz":
       (Var("googlecode_url") % "rlz") + "/trunk@32",
 
     # Dependencies used by libjpeg-turbo
     "src/third_party/yasm/binaries":
       "/trunk/deps/third_party/yasm/binaries@66803",
   },
   "mac": {
     "src/chrome/tools/test/reference_build/chrome_mac":
-      "/trunk/deps/reference_builds/chrome_mac@70124",
+      "/trunk/deps/reference_builds/chrome_mac@71120",
 
     "src/third_party/GTM":
       (Var("googlecode_url") % "google-toolbox-for-mac") + "/trunk@425",
     "src/third_party/pdfsqueeze":
       (Var("googlecode_url") % "pdfsqueeze") + "/trunk@2",
     "src/third_party/lighttpd":
       "/trunk/deps/third_party/lighttpd@33737",
 
     "src/third_party/WebKit/WebKit/mac":
       Var("webkit_trunk") + "/WebKit/mac@" + Var("webkit_revision"),
@@ skipping 58 matching lines @@
 ]
 
 
 hooks = [
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "pattern": ".",
     "action": ["python", "src/build/gyp_chromium"],
   },
 ]