Change reconcilor to use the MultiLogin flow for all non-DICE platforms.

This CL enables the UseMultiloginEndpoint feature on all non-DICE
platforms (including ChromeOS). Note that the feature is not yet removed
as will be kept until M80 branches to ensure we have a kill switch in
case it is needed.

Bug: 1013610
Change-Id: Idd3f79c63e2e3656a52b14e0c46b9d808e40c9f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1855988Reviewed-by: Kush Sinha <sinhak@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: Mihai Sardarescu <msarda@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708132}

components/signin/core/browser/account_reconcilor.cc

@@ -40,12 +40,12 @@
 using signin::AccountReconcilorDelegate;
 using signin_metrics::AccountReconcilorState;
 
-#if defined(OS_ANDROID) || defined(OS_IOS)
+#if BUILDFLAG(ENABLE_DICE_SUPPORT)
 const base::Feature kUseMultiloginEndpoint{"UseMultiloginEndpoint",
-                                           base::FEATURE_ENABLED_BY_DEFAULT};
+                                           base::FEATURE_DISABLED_BY_DEFAULT};
 #else
 const base::Feature kUseMultiloginEndpoint{"UseMultiloginEndpoint",
-                                           base::FEATURE_DISABLED_BY_DEFAULT};
+                                           base::FEATURE_ENABLED_BY_DEFAULT};
 #endif
 
 namespace {

components/signin/core/browser/account_reconcilor_unittest.cc

@@ -2043,6 +2043,9 @@ const std::vector<AccountReconcilorTestTableParam> kActiveDirectoryParams = {
 // clang-format on
 
 TEST_P(AccountReconcilorTestActiveDirectory, TableRowTestMergeSession) {
+  base::test::ScopedFeatureList scoped_feature_list;
+  scoped_feature_list.InitAndDisableFeature(kUseMultiloginEndpoint);
+
   // Setup tokens.
   std::vector<Token> tokens = ParseTokenString(GetParam().tokens);
   SetupTokens(GetParam().tokens);