[Experimental Framework] Move the trial token public key out of content and into the embedder.

content/public/common/content_client.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_
 #define CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 135 matching lines @@
   // trustworthy schemes should be added.
   virtual void AddServiceWorkerSchemes(std::set<std::string>* schemes) {}
 
   // Returns true if the embedder wishes to supplement the site isolation policy
   // used by the content layer. Returning true enables the infrastructure for
   // out-of-process iframes, and causes the content layer to consult
   // ContentBrowserClient::DoesSiteRequireDedicatedProcess() when making process
   // model decisions.
   virtual bool IsSupplementarySiteIsolationModeEnabled();
 
+  // Returns the public key to be used for origin trials, or nullptr if origin
+  // trials are not enabled in this context.
+  virtual base::StringPiece GetOriginTrialPublicKey();
+
  private:
   friend class ContentClientInitializer;  // To set these pointers.
   friend class InternalTestInitializer;
 
   // The embedder API for participating in browser logic.
   ContentBrowserClient* browser_;
   // The embedder API for participating in plugin logic.
   ContentPluginClient* plugin_;
   // The embedder API for participating in renderer logic.
   ContentRendererClient* renderer_;
   // The embedder API for participating in utility logic.
   ContentUtilityClient* utility_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_CONTENT_CLIENT_H_