[Dice] Improve the Signin.DiceResponseHeader histogram

- Now records "EnableSync" responses
- Now records "SignoutPrimary" correctly during Dice migration

Bug: 736310
Change-Id: I5b4e8e60ecaab18cac2454986f5849565529976a
Reviewed-on: https://chromium-review.googlesource.com/891220Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532823}

chrome/browser/signin/dice_response_handler.cc

@@ -49,6 +49,8 @@ enum DiceResponseHeader {
   kSignoutPrimary = 1,
   // Received a signout header for other account(s).
   kSignoutSecondary = 2,
+  // Received a "EnableSync" header.
+  kEnableSync = 3,
 
   kDiceResponseHeaderCount
 };
@@ -312,6 +314,7 @@ void DiceResponseHandler::ProcessEnableSyncHeader(
     const std::string& email,
     std::unique_ptr<ProcessDiceHeaderDelegate> delegate) {
   VLOG(1) << "Start processing Dice enable sync response";
+  RecordDiceResponseHeader(kEnableSync);
   for (auto it = token_fetchers_.begin(); it != token_fetchers_.end(); ++it) {
     DiceTokenFetcher* fetcher = it->get();
     if (fetcher->gaia_id() == gaia_id) {
@@ -340,20 +343,21 @@ void DiceResponseHandler::ProcessDiceSignoutHeader(
 
   // If one of the signed out accounts is the main Chrome account, then force a
   // complete signout. Otherwise simply revoke the corresponding tokens.
-  std::string current_account = signin_manager_->GetAuthenticatedAccountId();
-  std::vector<std::string> signed_out_accounts;
+  std::string primary_account = signin_manager_->GetAuthenticatedAccountId();
+  std::vector<std::string> secondary_accounts;
   for (const auto& account_info : account_infos) {
     std::string signed_out_account =
         account_tracker_service_->PickAccountIdForAccount(account_info.gaia_id,
                                                           account_info.email);
-    if (signed_out_account == current_account) {
+    if (signed_out_account == primary_account) {
+      RecordDiceResponseHeader(kSignoutPrimary);
+
       // If Dice migration is not complete, the token for the main account must
       // not be deleted when signing out of the web.
       if (!signin::IsDiceEnabledForProfile(signin_client_->GetPrefs()))
         continue;
 
       VLOG(1) << "[Dice] Signing out all accounts.";
-      RecordDiceResponseHeader(kSignoutPrimary);
       signin_manager_->SignOutAndRemoveAllAccounts(
           signin_metrics::SERVER_FORCED_DISABLE,
           signin_metrics::SignoutDelete::IGNORE_METRIC);
@@ -361,12 +365,16 @@ void DiceResponseHandler::ProcessDiceSignoutHeader(
       token_fetchers_.clear();
       return;
     } else {
-      signed_out_accounts.push_back(signed_out_account);
+      secondary_accounts.push_back(signed_out_account);
     }
   }
 
-  RecordDiceResponseHeader(kSignoutSecondary);
-  for (const auto& account : signed_out_accounts) {
+  if (signin::IsDiceEnabledForProfile(signin_client_->GetPrefs()) ||
+      secondary_accounts.size() == account_infos.size()) {
+    RecordDiceResponseHeader(kSignoutSecondary);
+  }
+
+  for (const auto& account : secondary_accounts) {
     VLOG(1) << "[Dice]: Revoking token for account: " << account;
     token_service_->RevokeCredentials(account);
     // If a token fetch is in flight for the same account, cancel it.

tools/metrics/histograms/enums.xml

@@ -39408,6 +39408,7 @@ Called by update_net_trust_anchors.py.-->
     Signout including the primary account.
   </int>
   <int value="2" label="SignoutSecondary">Signout only secondary accounts.</int>
+  <int value="3" label="EnableSync">Enable Sync after signin.</int>
 </enum>
 
 <enum name="SigninDiceTokenFetchResult">