Store Origin Trials public key in browser prefs

chrome/browser/prefs/origin_trial_prefs.cc

Index: chrome/browser/prefs/origin_trial_prefs.cc
diff --git a/chrome/browser/prefs/origin_trial_prefs.cc b/chrome/browser/prefs/origin_trial_prefs.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0c17d066964793bf688c6f311fd88eeb643064f5
--- /dev/null
+++ b/chrome/browser/prefs/origin_trial_prefs.cc
@@ -0,0 +1,14 @@
+// Copyright (c) 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.
+
+#include "chrome/browser/prefs/origin_trial_prefs.h"
+
+#include "base/values.h"
+#include "chrome/common/pref_names.h"
+#include "components/prefs/pref_registry_simple.h"
+
+void RegisterOriginTrialPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterStringPref(prefs::kOriginTrialPublicKey,
+                               "fMS4mpO6buLQ/QMd+zJmxzty/VQ6B1EUZqoCU04zoRU=");

[chasej, 2016/06/07 15:09:40]

I assume this value is the base64-encoded version of the default public key in
OriginTrialKeyManager (kDefaultPublicKey)? 

If so, why do we need to store two copies of the same value? I think it would be
better to just register an empty string as the default value here. Besides
avoiding a copy, it also means that the default public key is defined in
OriginTrialKeyManager, where it is most likely to be looked for/found.

[iclelland, 2016/06/08 02:48:22]

Yes, one copy is much better. Done.

+}