Support delta-compressed variations server responses.

chrome/browser/metrics/variations/variations_service.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_METRICS_VARIATIONS_VARIATIONS_SERVICE_H_
 #define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SERVICE_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 134 matching lines @@
   // disabled.
   std::string GetInvalidVariationsSeedSignature() const;
 
  protected:
   // Starts the fetching process once, where |OnURLFetchComplete| is called with
   // the response.
   virtual void DoActualFetch();
 
   // Stores the seed to prefs. Set as virtual and protected so that it can be
   // overridden by tests.
-  virtual void StoreSeed(const std::string& seed_data,
+  virtual bool StoreSeed(const std::string& seed_data,
                          const std::string& seed_signature,
-                         const base::Time& date_fetched);
+                         const std::string& country_code,
+                         const base::Time& date_fetched,
+                         bool is_delta_compressed);
 
   // Creates the VariationsService with the given |local_state| prefs service
   // and |state_manager|. This instance will take ownership of |notifier|.
   // Does not take ownership of |state_manager|. Caller should ensure that
   // |state_manager| is valid for the lifetime of this class. Use the |Create|
   // factory method to create a VariationsService.
   VariationsService(web_resource::ResourceRequestAllowedNotifier* notifier,
                     PrefService* local_state,
                     metrics::MetricsStateManager* state_manager);
 
@@ skipping 83 matching lines @@
   // The URL to use for querying the variations server.
   GURL variations_server_url_;
 
   // Tracks whether |CreateTrialsFromSeed| has been called, to ensure that
   // it gets called prior to |StartRepeatedVariationsSeedFetch|.
   bool create_trials_from_seed_called_;
 
   // Tracks whether the initial request to the variations server had completed.
   bool initial_request_completed_;
 
+  // Indicates that the next request to the variations service shouldn't specify
+  // that it supports delta compression. Set to true when a delta compressed
+  // response encountered an error.
+  bool disable_deltas_for_next_request_;
+
   // Helper class used to tell this service if it's allowed to make network
   // resource requests.
   scoped_ptr<web_resource::ResourceRequestAllowedNotifier>
       resource_request_allowed_notifier_;
 
   // The start time of the last seed request. This is used to measure the
   // latency of seed requests. Initially zero.
   base::TimeTicks last_request_started_time_;
 
   // The number of requests to the variations server that have been performed.
@@ skipping 10 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<VariationsService> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VariationsService);
 };
 
 }  // namespace chrome_variations
 
 #endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SERVICE_H_