Add proto for TLS error assistant, refactor proto generator code.

chrome/browser/resources/ssl/tls_error_assistant/tls_error_assistant.asciipb

Index: chrome/browser/resources/ssl/tls_error_assistant/tls_error_assistant.asciipb
diff --git a/chrome/browser/resources/ssl/tls_error_assistant/tls_error_assistant.asciipb b/chrome/browser/resources/ssl/tls_error_assistant/tls_error_assistant.asciipb
new file mode 100644
index 0000000000000000000000000000000000000000..a6714bf5a0e95fdc9863c3fee4b5396ac3f87521
--- /dev/null
+++ b/chrome/browser/resources/ssl/tls_error_assistant/tls_error_assistant.asciipb
@@ -0,0 +1,18 @@
+# Copyright 2016 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.
+
+# Placeholder for list of known certificates that are treated as captive
+# portal certificates.
+
+# TODO(crbug.com/640835): Populate this with full list.
+version_id: 1
+
+# See chrome/browser/ssl/tls_error_assistant.proto for the full format.
+captive_portal_cert {
+
+  # Sha256 hash of the certificate's public key. The fingerprint is prefixed
+  # with "sha256/" and encoded in base64 (same format as
+  # src/net/http/transport_security_state_static.pins)
+  sha256_hash: "sha256/AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
+}