X-Chrome-Variations logic refactoring

chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.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 CHROME_BROWSER_RENDERER_HOST_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 #define CHROME_BROWSER_RENDERER_HOST_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_
 
 #include <set>
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
-#include "base/metrics/field_trial.h"
-#include "chrome/common/metrics/variations/variation_ids.h"
 #include "content/public/browser/resource_dispatcher_host_delegate.h"
 
 class DelayedResourceQueue;
 class DownloadRequestLimiter;
 class SafeBrowsingService;
 
 namespace extensions {
 class UserScriptListener;
 }
 
 namespace prerender {
 class PrerenderTracker;
 }
 
 // Implements ResourceDispatcherHostDelegate. Currently used by the Prerender
 // system to abort requests and add to the load flags when a request begins.
 class ChromeResourceDispatcherHostDelegate
-    : public content::ResourceDispatcherHostDelegate,
-      public base::FieldTrialList::Observer {
+    : public content::ResourceDispatcherHostDelegate {
  public:
   // This class does not take ownership of the tracker but merely holds a
   // reference to it to avoid accessing g_browser_process.
   // |prerender_tracker| must outlive |this|.
   explicit ChromeResourceDispatcherHostDelegate(
       prerender::PrerenderTracker* prerender_tracker);
   virtual ~ChromeResourceDispatcherHostDelegate();
 
   // ResourceDispatcherHostDelegate implementation.
   virtual bool ShouldBeginRequest(
@@ skipping 37 matching lines @@
       net::URLRequest* request,
       content::ResourceContext* resource_context,
       content::ResourceResponse* response,
       IPC::Sender* sender) OVERRIDE;
   virtual void OnRequestRedirected(
       const GURL& redirect_url,
       net::URLRequest* request,
       content::ResourceContext* resource_context,
       content::ResourceResponse* response) OVERRIDE;
 
-  // base::FieldTrialList::Observer implementation.
-  // This will add the variation ID associated with |trial_name| and
-  // |group_name| to the variation ID cache.
-  virtual void OnFieldTrialGroupFinalized(
-      const std::string& trial_name,
-      const std::string& group_name) OVERRIDE;
-
  private:
   void AppendStandardResourceThrottles(
       net::URLRequest* request,
       content::ResourceContext* resource_context,
       int child_id,
       int route_id,
       ResourceType::Type resource_type,
       ScopedVector<content::ResourceThrottle>* throttles);
 
   // Adds Chrome experiment and metrics state as custom headers to |request|.
   // This is a best-effort attempt, and does not interrupt the request if the
   // headers can not be appended.
   void AppendChromeMetricsHeaders(
       net::URLRequest* request,
       content::ResourceContext* resource_context,
       ResourceType::Type resource_type);
 
 #if defined(ENABLE_ONE_CLICK_SIGNIN)
   // Append headers required to tell Gaia whether the sync interstitial
   // should be shown or not.  This header is only added for valid Gaia URLs.
   void AppendChromeSyncGaiaHeader(
       net::URLRequest* request,
       content::ResourceContext* resource_context);
 #endif
 
-  // Prepares the variation IDs cache with initial values if not already done.
-  // This method also registers the caller with the FieldTrialList to receive
-  // new variation IDs.
-  void InitVariationIDsCacheIfNeeded();
-
-  // Takes whatever is currently in |variation_ids_set_| and recreates
-  // |variation_ids_header_| with it.
-  void UpdateVariationIDsHeaderValue();
-
   scoped_refptr<DownloadRequestLimiter> download_request_limiter_;
   scoped_refptr<SafeBrowsingService> safe_browsing_;
   scoped_refptr<extensions::UserScriptListener> user_script_listener_;
   prerender::PrerenderTracker* prerender_tracker_;
 
-  // Whether or not we've initialized the Cache.
-  bool variation_ids_cache_initialized_;
-
-  // Keep a cache of variation IDs that are transmitted in headers to Google.
-  // This consists of a list of valid IDs, and the actual transmitted header.
-  // Note that since this cache is both initialized and accessed from the IO
-  // thread, we do not need to synchronize its uses.
-  std::set<chrome_variations::VariationID> variation_ids_set_;
-  std::string variation_ids_header_;
-
   DISALLOW_COPY_AND_ASSIGN(ChromeResourceDispatcherHostDelegate);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_CHROME_RESOURCE_DISPATCHER_HOST_DELEGATE_H_