Variations seed is pulled from the Java application on the first launch of Chrome

components/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 "components/variations/variations_seed_store.h"
 
 #include "base/base64.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/numerics/safe_math.h"
 #include "base/prefs/pref_registry_simple.h"
@@ skipping 321 matching lines @@
 void VariationsSeedStore::ClearPrefs() {
   local_state_->ClearPref(prefs::kVariationsCompressedSeed);
   local_state_->ClearPref(prefs::kVariationsSeed);
   local_state_->ClearPref(prefs::kVariationsSeedDate);
   local_state_->ClearPref(prefs::kVariationsSeedSignature);
 }
 
 bool VariationsSeedStore::ReadSeedData(std::string* seed_data) {
   std::string base64_seed_data =
       local_state_->GetString(prefs::kVariationsCompressedSeed);
-  const bool is_compressed = !base64_seed_data.empty();
+
+  // ToDo (agulenko): return const identifier back
+  /* const */ bool is_compressed = !base64_seed_data.empty();
+
   // If there's no compressed seed, fall back to the uncompressed one.
   if (!is_compressed)
     base64_seed_data = local_state_->GetString(prefs::kVariationsSeed);
 
   if (base64_seed_data.empty()) {
+#if defined(OS_ANDROID)
+    LOG(WARNING) << "variationsTracker: Trying to read seed from Java side";

[Steven Holte, 2015/10/28 01:00:18]

Move this block of code into a function, e.g. MigrateJavaSeed.

[Alexei Svitkine (slow), 2015/10/28 15:16:38]

Agree with Steve. How about naming it ImportJavaSeed()? I think that's a little
bit clearer than Migrate, which can mean different things.

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+    std::string plain_seed_data = pull_variations_seed_pref_.Run(
+        prefs::kVariationsSeed);
+    std::string seed_signature = pull_variations_seed_pref_.Run(
+        prefs::kVariationsSeedSignature);
+    std::string country_code = pull_variations_seed_pref_.Run(
+        prefs::kVariationsCountry);
+
+    if (plain_seed_data.empty()) {
+      RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_EMPTY);
+      return false;
+    }
+
+    // ToDo (agulenko): pull actual time from the response.

[Alexei Svitkine (slow), 2015/10/28 15:16:38]

Nit: Usual format for these is:

TODO(agulenko): Pull actual time from the response.

(Also, I'm ok with this being a TODO for this CL and can be implemented in a
follow-up CL).

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+    base::Time current_time = base::Time::Now();
+    scoped_ptr<variations::VariationsSeed> seed(new variations::VariationsSeed);

[Alexei Svitkine (slow), 2015/10/28 15:16:38]

It doesn't seem like you're using |seed| other than the param below. Since the
param can be nullptr, just pass that in instead.

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+
+    // Trying to translated the seed that we pulled from the Java side.

[Steven Holte, 2015/10/28 01:00:18]

translate -> migrate, but moving to a function should make this comment
unnecessary.

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+    // ToDo(agulenko): replace "true" with real value 

[Steven Holte, 2015/10/28 01:00:18]

Nit: All caps TODO

[Steven Holte, 2015/10/28 01:00:18]

Probably TODO: support gzipped seed?

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+    if (!StoreSeedData(plain_seed_data, seed_signature, country_code,
+                       current_time, false, false, seed.get())) {
+      LOG(WARNING) << "Seed translation failed!";

[Steven Holte, 2015/10/28 01:00:18]

Change to "First run variations seed is invalid"

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+      return false;
+    }

[Steven Holte, 2015/10/28 01:00:18]

Add a TODO to clear the Java prefs (regardless if StoreSeedData fails)

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+
+    base64_seed_data = local_state_->GetString(prefs::kVariationsCompressedSeed);

[Steven Holte, 2015/10/28 01:00:18]

To avoid this duplication it's probably better to do the migration before the
first attempt to load the seed, e.g. change

bool VariationsSeedStore::LoadSeed(variations::VariationsSeed* seed) {
  invalid_base64_signature_.clear();

  std::string seed_data;
  if (!ReadSeedData(&seed_data))
    return false;

to 


bool VariationsSeedStore::LoadSeed(variations::VariationsSeed* seed) {
  invalid_base64_signature_.clear();

  if (!local_state_->HasPrefPath(prefs::kVariationsSeedSignature))
     MigrateJavaSeed();

  std::string seed_data;
  if (!ReadSeedData(&seed_data))
    return false;

[Alexander Agulenko, 2015/10/28 23:05:09]

Done.

+    is_compressed = !base64_seed_data.empty();
+
+    // If there's no compressed seed, fall back to the uncompressed one.
+    if (!is_compressed) {
+      base64_seed_data = local_state_->GetString(prefs::kVariationsSeed);
+    }
+#else  // OS_ANDROID
     RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_EMPTY);
     return false;
+#endif  // OS_ANDROID
   }
 
   // If the decode process fails, assume the pref value is corrupt and clear it.
   std::string decoded_data;
   if (!base::Base64Decode(base64_seed_data, &decoded_data)) {
     ClearPrefs();
     RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_CORRUPT_BASE64);
     return false;
   }
 
@@ skipping 117 matching lines @@
   }
   return true;
 }
 
 void VariationsSeedStore::ReportUnsupportedSeedFormatError() {
   RecordSeedStoreHistogram(
       VARIATIONS_SEED_STORE_FAILED_UNSUPPORTED_SEED_FORMAT);
 }
 
 }  // namespace variations