Add experiment to exercise AffiliationService with dummy data, plus add related UMA histograms.

components/password_manager/core/browser/affiliation_utils.cc

Index: components/password_manager/core/browser/affiliation_utils.cc
diff --git a/components/password_manager/core/browser/affiliation_utils.cc b/components/password_manager/core/browser/affiliation_utils.cc
index 13c417aa4dd8704b9d2c318fb67e7f4dc74a8b84..fa911ffbd4ff2b0e8f40559988429dba883e836a 100644
--- a/components/password_manager/core/browser/affiliation_utils.cc
+++ b/components/password_manager/core/browser/affiliation_utils.cc
@@ -320,6 +320,17 @@ bool IsPropagatingPasswordChangesToWebCredentialsEnabled(
   return LowerCaseEqualsASCII(update_enabled, "enabled");
 }
 
+bool IsAffiliationRequestsForDummyFacetsEnabled(
+    const base::CommandLine& command_line) {
+  const std::string synthesizing_enabled = variations::GetVariationParamValue(
+      kFieldTrialName, "affiliation_requests_for_dummy_facets");
+  if (command_line.HasSwitch(switches::kDisableAffiliationBasedMatching))
+    return false;
+  if (command_line.HasSwitch(switches::kEnableAffiliationBasedMatching))
+    return true;
+  return LowerCaseEqualsASCII(synthesizing_enabled, "enabled");
+}
+
 bool IsValidAndroidFacetURI(const std::string& url) {
   FacetURI facet = FacetURI::FromPotentiallyInvalidSpec(url);
   return facet.IsValidAndroidFacetURI();