Disable history delete directives when sessions are encrypted.

chrome/browser/sync/profile_sync_service.cc

Index: chrome/browser/sync/profile_sync_service.cc
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index b3d6c949226f287a9032e9be27f8924b492f4862..289917726b4bd77763f2a9af6084a8f1cb29b53c 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -1117,6 +1117,15 @@ void ProfileSyncService::OnEncryptedTypesChanged(
            << " (encrypt everything is set to "
            << (encrypt_everything_ ? "true" : "false") << ")";
   DCHECK(encrypted_types_.Has(syncer::PASSWORDS));
+
+  // If sessions are encrypted, full history sync is not possible, and
+  // delete directives are unnecessary.
+  if (GetPreferredDataTypes().Has(syncer::HISTORY_DELETE_DIRECTIVES) &&
+      encrypted_types_.Has(syncer::SESSIONS)) {
+    DisableBrokenDatatype(syncer::HISTORY_DELETE_DIRECTIVES,
+                          FROM_HERE,
+                          "Delete directives not supported with encryption.");
+  }
 }
 
 void ProfileSyncService::OnEncryptionComplete() {