[Cleanup] Remove the obsolete variations_seed pref.

components/variations/variations_seed_store.cc

Index: components/variations/variations_seed_store.cc
diff --git a/components/variations/variations_seed_store.cc b/components/variations/variations_seed_store.cc
index 647cc8dbf9cba17a2d2f09cc77762dccf168874b..31c6ef520f817d330f3a7b5a20915619e2b7ae3c 100644
--- a/components/variations/variations_seed_store.cc
+++ b/components/variations/variations_seed_store.cc
@@ -307,7 +307,6 @@ std::string VariationsSeedStore::GetInvalidSignature() const {
 // static
 void VariationsSeedStore::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterStringPref(prefs::kVariationsCompressedSeed, std::string());
-  registry->RegisterStringPref(prefs::kVariationsSeed, std::string());
   registry->RegisterInt64Pref(prefs::kVariationsSeedDate,
                               base::Time().ToInternalValue());
   registry->RegisterStringPref(prefs::kVariationsSeedSignature, std::string());
@@ -345,7 +344,6 @@ VariationsSeedStore::VerifySeedSignature(
 
 void VariationsSeedStore::ClearPrefs() {
   local_state_->ClearPref(prefs::kVariationsCompressedSeed);
-  local_state_->ClearPref(prefs::kVariationsSeed);
   local_state_->ClearPref(prefs::kVariationsSeedDate);
   local_state_->ClearPref(prefs::kVariationsSeedSignature);
 }
@@ -387,11 +385,6 @@ void VariationsSeedStore::ImportFirstRunJavaSeed() {
 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();
-  // 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()) {
     RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_EMPTY);
     return false;
@@ -405,9 +398,7 @@ bool VariationsSeedStore::ReadSeedData(std::string* seed_data) {
     return false;
   }
 
-  if (!is_compressed) {
-    seed_data->swap(decoded_data);
-  } else if (!compression::GzipUncompress(decoded_data, seed_data)) {
+  if (!compression::GzipUncompress(decoded_data, seed_data)) {
     ClearPrefs();
     RecordVariationSeedEmptyHistogram(VARIATIONS_SEED_CORRUPT_GZIP);
     return false;
@@ -455,10 +446,6 @@ bool VariationsSeedStore::StoreSeedDataNoDelta(
   std::string base64_seed_data;
   base::Base64Encode(compressed_seed_data, &base64_seed_data);
 
-  // TODO(asvitkine): This pref is no longer being used. Remove it completely
-  // in M45+.
-  local_state_->ClearPref(prefs::kVariationsSeed);

[gab, 2017/06/06 14:45:03]

Since this pref was passed through master_prefs and manually copied in Local
State I'd expect it to also be found in Preferences for the Default profile as
all master_preferences are copied to Preferences on first run (or am I not
seeing code that was stripping it from master_prefs before that copy?)

[Ilya Sherman, 2017/06/06 20:22:16]

Hmm, that sounds like a bug if this and the other related prefs aren't being
stripped -- the prefs should never be read from anywhere other than Local State.
 I'm not sure how to test with master_prefs -- is there documentation for it
someswhere?

[Ilya Sherman, 2017/06/06 21:54:37]

Okay, found the docs [1] and then updated them for Mac based on the code [2]. 
You're right, all of the variations_* prefs are being copied into the Default
profile.  I filed https://crbug.com/730204

[1]
https://sites.google.com/a/chromium.org/dev/administrators/configuring-other-...
[2]
https://cs.chromium.org/chromium/src/chrome/browser/mac/master_prefs.mm?q=chr...

-
 #if defined(OS_ANDROID)
   // If currently we do not have any stored pref then we mark seed storing as
   // successful on the Java side of Chrome for Android to avoid repeated seed