Extend VariationParamsManager to support feature associations.

components/ntp_snippets/ntp_snippets_fetcher_unittest.cc

Index: components/ntp_snippets/ntp_snippets_fetcher_unittest.cc
diff --git a/components/ntp_snippets/ntp_snippets_fetcher_unittest.cc b/components/ntp_snippets/ntp_snippets_fetcher_unittest.cc
index 48380dee5bac59ab59044a2b8a1b1fec04da9b03..b631d72afd7144771a58c2b2a238f3a93982dde2 100644
--- a/components/ntp_snippets/ntp_snippets_fetcher_unittest.cc
+++ b/components/ntp_snippets/ntp_snippets_fetcher_unittest.cc
@@ -24,7 +24,7 @@
 #include "components/signin/core/browser/fake_signin_manager.h"
 #include "components/signin/core/browser/test_signin_client.h"
 #include "components/variations/entropy_provider.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"
@@ -153,7 +153,7 @@ class NTPSnippetsFetcherTest : public testing::Test {
 
   NTPSnippetsFetcherTest(const GURL& gurl,
                          const std::map<std::string, std::string>& params)
-      : params_manager_(ntp_snippets::kStudyName, params),
+      : params_manager_(ntp_snippets::kStudyName, params, {}),
         mock_task_runner_(new base::TestMockTimeTaskRunner()),
         mock_task_runner_handle_(mock_task_runner_),
         signin_client_(new TestSigninClient(nullptr)),