Make VariationsService simulate received seeds.

chrome/browser/metrics/variations/variations_seed_store.cc

 // 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.
 
 #include "chrome/browser/metrics/variations/variations_seed_store.h"
 
 #include "base/base64.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
@@ skipping 144 matching lines @@
   }
 
   variations_serial_number_ = seed->serial_number();
   RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_NOT_EMPTY);
   return true;
 }
 
 bool VariationsSeedStore::StoreSeedData(
     const std::string& seed_data,
     const std::string& base64_seed_signature,
-    const base::Time& date_fetched) {
+    const base::Time& date_fetched,
+    VariationsSeed* seed) {

[jwd, 2014/04/25 14:30:34]

Should you check that seed isn't null?

[Alexei Svitkine (slow), 2014/04/25 15:21:46]

Changed logic to allow passing NULL and only filling the out param on success,
and updated function declaration comment.

   if (seed_data.empty()) {
     VLOG(1) << "Variations seed data is empty, rejecting the seed.";
     return false;
   }
 
   // Only store the seed data if it parses correctly.
-  VariationsSeed seed;
-  if (!seed.ParseFromString(seed_data)) {
+  if (!seed->ParseFromString(seed_data)) {

[jwd, 2014/04/25 14:30:34]

What's in seed when it fails to parse? Should it be cleared before returning? I
don't feel strongly that it should.

[Alexei Svitkine (slow), 2014/04/25 15:21:46]

Ditto.

     VLOG(1) << "Variations seed data is not in valid proto format, "
             << "rejecting the seed.";
     return false;
   }
 
   const VerifySignatureResult result =
       VerifySeedSignature(seed_data, base64_seed_signature);
   if (result != VARIATIONS_SEED_SIGNATURE_ENUM_SIZE) {
     UMA_HISTOGRAM_ENUMERATION("Variations.StoreSeedSignature", result,
                               VARIATIONS_SEED_SIGNATURE_ENUM_SIZE);
     if (result != VARIATIONS_SEED_SIGNATURE_VALID) {
       VLOG(1) << "Variations seed signature missing or invalid with result: "
               << result << ". Rejecting the seed.";
       return false;
     }
   }
 
   std::string base64_seed_data;
   base::Base64Encode(seed_data, &base64_seed_data);
 
   // TODO(asvitkine): This pref is no longer being used. Remove it completely
   // in a couple of releases.
   local_state_->ClearPref(prefs::kVariationsSeedHash);
 
   local_state_->SetString(prefs::kVariationsSeed, base64_seed_data);
   UpdateSeedDateAndLogDayChange(date_fetched);
   local_state_->SetString(prefs::kVariationsSeedSignature,
                           base64_seed_signature);
-  variations_serial_number_ = seed.serial_number();
+  variations_serial_number_ = seed->serial_number();
 
   return true;
 }
 
 void VariationsSeedStore::UpdateSeedDateAndLogDayChange(
     const base::Time& server_date_fetched) {
   VariationsSeedDateChangeState date_change = SEED_DATE_NO_OLD_DATE;
 
   if (local_state_->HasPrefPath(prefs::kVariationsSeedDate)) {
     const int64 stored_date_value =
@@ skipping 50 matching lines @@
   }
 
   verifier.VerifyUpdate(reinterpret_cast<const uint8*>(seed_bytes.data()),
                         seed_bytes.size());
   if (verifier.VerifyFinal())
     return VARIATIONS_SEED_SIGNATURE_VALID;
   return VARIATIONS_SEED_SIGNATURE_INVALID_SEED;
 }
 
 }  // namespace chrome_variations