Address more TODO(GYP) in the GN build.

components/crash/content/app/BUILD.gn

 # Copyright 2014 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.
 
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 source_set("lib") {
   sources = [
@@ skipping 169 matching lines @@
     if (is_mac) {
       deps += [ "//breakpad" ]
     }
 
     if (is_win) {
       deps += [ "//breakpad:breakpad_handler" ]
       libs = [ "userenv.lib" ]
     }
   }
 }
+
+if (is_mac) {
+  source_set("breakpad_stubs") {
+    sources = [
+      "breakpad_mac.h",
+      "breakpad_mac_stubs.mm",
+      "crash_reporter_client.cc",
+      "crash_reporter_client.h",
+    ]
+    deps = [
+      "//base",
+    ]
+  }
+}
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [
+    "crash_keys_win_unittest.cc",

[brucedawson, 2016/05/06 18:38:36]

Note that this is fixing part of bug 604060, so add that reference to the BUG=
part of the description.

[brucedawson, 2016/05/09 19:09:18]

Also, the file name suggests that this is a Windows only file, but in gyp builds
it was compiled for all. ???

[brettw, 2016/05/09 21:08:34]

The platform-filter should remove "*_win_unittest.cc" files from both GYP and GN
builds.

+  ]
+  deps = [
+    ":lib",
+    "//base",
+    "//testing/gmock",
+    "//testing/gtest",
+  ]
+}