Add manual tools for kerberos testing on android

- App for providing an account for authentication
- dummy server to reply with the appropriate headers
- policy configuration
- setup documentation

BUG=534293

Review URL: https://codereview.chromium.org/1355103002

Cr-Commit-Position: refs/heads/master@{#354752}
diff --git a/BUILD.gn b/BUILD.gn
index 7b3c67d9f..02b4f23 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -239,6 +239,7 @@
       "//third_party/errorprone:chromium_errorprone",
       "//tools/android:android_tools",
       "//tools/android/heap_profiler:heap_profiler_unittests",
+      "//tools/android/kerberos/SpnegoAuthenticator:spnego_authenticator_apk",
       "//tools/imagediff($host_toolchain)",
 
       # TODO(GYP): Remove these when the components_unittests work.