Extend VariationParamsManager to support feature associations.

components/ntp_snippets/ntp_snippets_service_unittest.cc

Index: components/ntp_snippets/ntp_snippets_service_unittest.cc
diff --git a/components/ntp_snippets/ntp_snippets_service_unittest.cc b/components/ntp_snippets/ntp_snippets_service_unittest.cc
index cd4cd7e0ad9a07fb4d0fb93bc3ac4409b48824a6..6fdbc7d066330c2e08105efec6170735cf3ff871 100644
--- a/components/ntp_snippets/ntp_snippets_service_unittest.cc
+++ b/components/ntp_snippets/ntp_snippets_service_unittest.cc
@@ -36,7 +36,7 @@
 #include "components/prefs/testing_pref_service.h"
 #include "components/signin/core/browser/fake_profile_oauth2_token_service.h"
 #include "components/signin/core/browser/fake_signin_manager.h"
-#include "components/variations/variations_associated_data.h"
+#include "components/variations/variations_params_manager.h"
 #include "google_apis/google_api_keys.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "net/url_request/url_request_test_util.h"
@@ -345,7 +345,7 @@ class NTPSnippetsServiceTest : public ::testing::Test {
   NTPSnippetsServiceTest()
       : params_manager_(ntp_snippets::kStudyName,
                         {{"content_suggestions_backend",
-                          kTestContentSuggestionsServerEndpoint}}),
+                          kTestContentSuggestionsServerEndpoint}}, {}),
         fake_url_fetcher_factory_(
             /*default_factory=*/&failing_url_fetcher_factory_),
         test_url_(base::StringPrintf(kTestContentSuggestionsServerFormat,