Address more TODO(GYP) in the GN build.

components/crash/content/app/BUILD.gn

Index: components/crash/content/app/BUILD.gn
diff --git a/components/crash/content/app/BUILD.gn b/components/crash/content/app/BUILD.gn
index 8d871fe8b6572eea1a72a08d3bdab496012805c5..bf13444fc34ca180f0c8c7623d9a95528ca8417f 100644
--- a/components/crash/content/app/BUILD.gn
+++ b/components/crash/content/app/BUILD.gn
@@ -187,3 +187,30 @@ source_set("app_breakpad_mac_win_to_be_deleted") {
     }
   }
 }
+
+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",
+  ]
+}