Simplify OriginTrialContext and the way it validates tokens.

third_party/WebKit/public/platform/WebTrialTokenValidator.h

 // 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.
 
 #ifndef WebTrialTokenValidator_h
 #define WebTrialTokenValidator_h
 
 #include "public/platform/WebCallbacks.h"
 #include "public/platform/WebSecurityOrigin.h"
 #include "public/platform/WebString.h"
 
 namespace blink {
 
 enum class WebOriginTrialTokenStatus;
 
 // This interface abstracts the task of validating a token for an experimental
 // feature. Experimental features can be turned on and off at runtime for a
 // specific renderer, depending on the presence of a valid token provided by
 // the origin.
 //
 // For more information, see https://github.com/jpchase/OriginTrials.
 
 class WebTrialTokenValidator {
 public:
     virtual ~WebTrialTokenValidator() {}
 
-    // Returns true if the given token is valid for the specified origin and
-    // feature name.
-    virtual WebOriginTrialTokenStatus validateToken(const WebString& token, const WebSecurityOrigin&, const WebString& featureName) = 0;
+    // Returns whether the given token is valid for the specified origin. If the
+    // token is valid, it also returns the feature the token is valid for in
+    // |*featureName|.
+    virtual WebOriginTrialTokenStatus validateToken(const WebString& token, const WebSecurityOrigin&, WebString* featureName) = 0;
 };
 
 } // namespace blink
 
 #endif // WebTrialTokenValidator_h