Remove httpDisplaynameHeader config option

As of change If91b1cb9393e2fcb67efde982c5889f4ca99bf17 this option isn't
used anymore.

Bug: Issue 40012596
Change-Id: I3aa4941ee77e41c66d8739964211e364c0d646c3
diff --git a/README.md b/README.md
index 9a01e03..2a7fa11 100644
--- a/README.md
+++ b/README.md
@@ -93,7 +93,6 @@
 	type = HTTP
     logoutUrl = https://mysso.example.com/logout
     httpHeader = X-SAML-UserName
-    httpDisplaynameHeader = X-SAML-DisplayName
     httpEmailHeader = X-SAML-EmailHeader
     httpExternalIdHeader = X-SAML-ExternalId
 ```
diff --git a/adfs/README.md b/adfs/README.md
index 693838c..c589619 100644
--- a/adfs/README.md
+++ b/adfs/README.md
@@ -17,7 +17,6 @@
         type = HTTP_LDAP
         logoutUrl = https://fs.hc.sct/adfs/ls/?wa=wsignout1.0
         httpHeader = X-SAML-UserName
-        httpDisplaynameHeader = X-SAML-DisplayName
         httpEmailHeader = X-SAML-EmailHeader
         httpExternalIdHeader = X-SAML-ExternalId
     [saml]
diff --git a/keycloak/README.md b/keycloak/README.md
index bf9939d..c88f2c4 100644
--- a/keycloak/README.md
+++ b/keycloak/README.md
@@ -38,7 +38,6 @@
     type = HTTP
     logoutUrl = http://localhost:8080/auth/realms/master/protocol/openid-connect/logout
     httpHeader = X-SAML-UserName
-    httpDisplaynameHeader = X-SAML-DisplayName
     httpEmailHeader = X-SAML-EmailHeader
     httpExternalIdHeader = X-SAML-ExternalId
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java b/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java
index 5b5c969..db129f9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java
@@ -126,17 +126,14 @@
     httpDisplaynameHeader = getHeaderFromConfig(gerritConfig, "httpDisplaynameHeader");
     httpEmailHeader = getHeaderFromConfig(gerritConfig, "httpEmailHeader");
     httpExternalIdHeader = getHeaderFromConfig(gerritConfig, "httpExternalIdHeader");
-    authHeaders =
-        Sets.newHashSet(
-            httpUserNameHeader, httpDisplaynameHeader, httpEmailHeader, httpExternalIdHeader);
+    authHeaders = Sets.newHashSet(httpUserNameHeader, httpEmailHeader, httpExternalIdHeader);
     if (authHeaders.contains("") || authHeaders.contains(null)) {
       throw new RuntimeException("All authentication headers must be set.");
     }
-    if (authHeaders.size() != 4) {
+    if (authHeaders.size() != 3) {
       throw new RuntimeException(
           "Unique values for httpUserNameHeader, "
-              + "httpDisplaynameHeader, httpEmailHeader and httpExternalIdHeader "
-              + "are required.");
+              + "httpEmailHeader and httpExternalIdHeader are required.");
     }
     userNameToLowerCase = gerritConfig.getBoolean("auth", "userNameToLowerCase", false);
 
@@ -353,8 +350,6 @@
       String nameUpperCase = name.toUpperCase();
       if (httpUserNameHeader.equals(nameUpperCase)) {
         return user.getUsername();
-      } else if (httpDisplaynameHeader.equals(nameUpperCase)) {
-        return user.getDisplayName();
       } else if (httpEmailHeader.equals(nameUpperCase)) {
         return user.getEmail();
       } else if (httpExternalIdHeader.equals(nameUpperCase)) {
diff --git a/src/test/java/com/googlesource/gerrit/plugins/saml/SamlWebFilterIT.java b/src/test/java/com/googlesource/gerrit/plugins/saml/SamlWebFilterIT.java
index 98aa3b6..249b447 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/saml/SamlWebFilterIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/saml/SamlWebFilterIT.java
@@ -36,7 +36,6 @@
             + "[auth]\n"
             + "    type = HTTP\n"
             + "    httpHeader = X-SAML-UserName\n"
-            + "    httpDisplaynameHeader = X-SAML-DisplayName\n"
             + "    httpEmailHeader = X-SAML-EmailHeader\n"
             + "    httpExternalIdHeader = X-SAML-ExternalId");
     return cfg;