Allow backgrounding processes on Mac

base/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # HOW TO WRITE CONDITIONALS IN THIS FILE
 # ======================================
 #
 # In many other places, one would write a conditional that expresses all the
 # cases when a source file is used or unused, and then either add or subtract
 # it from the sources list in that case
@@ skipping 632 matching lines @@
     "process/process_iterator.cc",
     "process/process_iterator.h",
 
     #"process/process_iterator_freebsd.cc",  # Unused in Chromium build.
     "process/process_iterator_linux.cc",
     "process/process_iterator_mac.cc",
 
     #"process/process_iterator_openbsd.cc",  # Unused in Chromium build.
     "process/process_iterator_win.cc",
     "process/process_linux.cc",
+    "process/process_mac.cc",
     "process/process_metrics.cc",
     "process/process_metrics.h",
 
     #"process/process_metrics_freebsd.cc",  # Unused in Chromium build.
     "process/process_metrics_ios.cc",
     "process/process_metrics_linux.cc",
     "process/process_metrics_mac.cc",
 
     #"process/process_metrics_openbsd.cc",  # Unused in Chromium build.
     "process/process_metrics_posix.cc",
@@ skipping 1790 matching lines @@
     testonly = true
     deps = [
       ":base_java",
     ]
     java_files = [
       "test/android/java/src/org/chromium/base/ContentUriTestUtils.java",
       "test/android/java/src/org/chromium/base/TestSystemMessageHandler.java",
     ]
   }
 }