Refactor OriginTrialPolicy to be an abstract interface in content/public/common

content/common/origin_trials/trial_token_validator.cc

 // 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.
 
 #include "content/common/origin_trials/trial_token_validator.h"
 
 #include "base/time/time.h"
 #include "content/common/origin_trials/trial_token.h"
 #include "content/public/common/content_client.h"
+#include "content/public/common/origin_trial_policy.h"
 #include "third_party/WebKit/public/platform/WebOriginTrialTokenStatus.h"
 
 namespace content {
 
 blink::WebOriginTrialTokenStatus TrialTokenValidator::ValidateToken(
     const std::string& token,
     const url::Origin& origin,
     base::StringPiece feature_name) {
+  const ContentClient* content_client = GetContentClient();
+  const OriginTrialPolicy* origin_trial_policy =
+      content_client->GetOriginTrialPolicy();
+  if (!origin_trial_policy)
+    return blink::WebOriginTrialTokenStatus::NotSupported;
+
   // TODO(iclelland): Allow for multiple signing keys, and iterate over all
   // active keys here. https://crbug.com/543220
-  ContentClient* content_client = GetContentClient();
-  base::StringPiece public_key = content_client->GetOriginTrialPublicKey();
+  base::StringPiece public_key = origin_trial_policy->GetPublicKey();
   if (public_key.empty()) {
     return blink::WebOriginTrialTokenStatus::NotSupported;
   }
 
   blink::WebOriginTrialTokenStatus status;
   std::unique_ptr<TrialToken> trial_token =
       TrialToken::From(token, public_key, &status);
   if (status != blink::WebOriginTrialTokenStatus::Success) {
     return status;
   }
 
   return trial_token->IsValidForFeature(origin, feature_name,
                                         base::Time::Now());
 }
 
 }  // namespace content