Restrict transmission of external exp ids to signed in users.

components/variations/variations_http_header_provider.h

 // Copyright 2014 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 COMPONENTS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_
 #define COMPONENTS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_
 
 #include <set>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/metrics/field_trial.h"
 #include "base/synchronization/lock.h"
 #include "components/variations/synthetic_trials.h"
 #include "components/variations/variations_associated_data.h"
 
 namespace base {
 template <typename T>
 struct DefaultSingletonTraits;
 }
 
 namespace variations {
 
 // A helper class for maintaining client experiments and metrics state
 // transmitted in custom HTTP request headers.
 // This class is a thread-safe singleton.
 class VariationsHttpHeaderProvider : public base::FieldTrialList::Observer,
                                      public SyntheticTrialObserver {
  public:
   static VariationsHttpHeaderProvider* GetInstance();
 
   // Returns the value of the client data header, computing and caching it if
-  // necessary.
-  std::string GetClientDataHeader();
+  // necessary. If |is_signed_in| is false, variation ids that should only be
+  // sent for signed in users will not be included.
+  std::string GetClientDataHeader(bool is_signed_in);
 
   // Returns a space-separated string containing the list of current active
   // variations (as would be reported in the |variation_id| repeated field of
-  // the ClientVariations proto). The returned string is guaranteed to have a
+  // the ClientVariations proto). Does not include variation ids that should be
+  // sent for signed-in users only. The returned string is guaranteed to have a
   // a leading and trailing space, e.g. " 123 234 345 ".
   std::string GetVariationsString();
 
   // Forces the list of |variation_ids| (which will be modified by adding the
   // comma-separated |command_line_variation_ids|). This is a wrapper function
   // around SetDefaultVariationIds.
   bool ForceVariationIds(
       const std::string& command_line_variation_ids,
       std::vector<std::string>* variation_ids);
 
   // Sets *additional* variation ids and trigger variation ids to be encoded in
   // the X-Client-Data request header. This is intended for development use to
   // force a server side experiment id. |variation_ids| should be a list of
   // strings of numeric experiment ids. If an id is prefixed with "t" it will
   // be treated as a trigger experiment id.
   bool SetDefaultVariationIds(const std::vector<std::string>& variation_ids);
 
   // Resets any cached state for tests.
   void ResetForTesting();
 
  private:
   friend struct base::DefaultSingletonTraits<VariationsHttpHeaderProvider>;
 
+  typedef std::pair<VariationID, IDCollectionKey> VariationIDEntry;
+
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            SetDefaultVariationIds_Valid);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            SetDefaultVariationIds_Invalid);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            OnFieldTrialGroupFinalized);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            GetVariationsString);
 
   VariationsHttpHeaderProvider();
   ~VariationsHttpHeaderProvider() override;
 
   // base::FieldTrialList::Observer:
   // This will add the variation ID associated with |trial_name| and
   // |group_name| to the variation ID cache.
   void OnFieldTrialGroupFinalized(const std::string& trial_name,
                                   const std::string& group_name) override;
 
   // metrics::SyntheticTrialObserver:
   void OnSyntheticTrialsChanged(
       const std::vector<SyntheticTrialGroup>& groups) override;
 
   // 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();
 
+  // Looks up the associated id for the given trial/group and adds an entry for
+  // it to |variation_ids_set_| if found.
+  void CacheVariationsId(const std::string& trial_name,
+                         const std::string& group_name,
+                         IDCollectionKey key);
+
   // Takes whatever is currently in |variation_ids_set_| and recreates
   // |variation_ids_header_| with it.  Assumes the the |lock_| is currently
   // held.
   void UpdateVariationIDsHeaderValue();
 
+  // Generates a base64-encoded proto to be used as a header value for the given
+  // |is_signed_in| state.
+  std::string GenerateBase64EncodedProto(bool is_signed_in);
+
   // Returns the currently active set of variation ids, which includes any
   // default values, synthetic variations and actual field trial variations.
-  std::set<VariationID> GetAllVariationIds();
+  std::set<VariationIDEntry> GetAllVariationIds();
 
-  // Guards |variation_ids_cache_initialized_|, |variation_ids_set_| and
-  // |variation_ids_header_|.
+  // Guards access to variables below.
   base::Lock lock_;
 
-  // Whether or not we've initialized the cache.
+  // Whether or not we've initialized the caches.
   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.
-  std::set<VariationID> variation_ids_set_;
-  std::set<VariationID> variation_trigger_ids_set_;
+  std::set<VariationIDEntry> variation_ids_set_;
 
   // Provides the google experiment ids forced from command line.
-  std::set<VariationID> default_variation_ids_set_;
-  std::set<VariationID> default_trigger_id_set_;
+  std::set<VariationIDEntry> default_variation_ids_set_;
 
   // Variations ids from synthetic field trials.
-  std::set<VariationID> synthetic_variation_ids_set_;
+  std::set<VariationIDEntry> synthetic_variation_ids_set_;
 
-  std::string variation_ids_header_;
+  std::string cached_variation_ids_header_;
+  std::string cached_variation_ids_header_signed_in_;
 
   DISALLOW_COPY_AND_ASSIGN(VariationsHttpHeaderProvider);
 };
 
 }  // namespace variations
 
 #endif  // COMPONENTS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_