Remove the unused method ProtoCompileActionBuilder#setLangPluginParameter().

RELNOTES: None.
PiperOrigin-RevId: 251605375
diff --git a/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilder.java
index 8720f5a..d2e438a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilder.java
@@ -22,7 +22,6 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Supplier;
-import com.google.common.base.Suppliers;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.AbstractAction;
@@ -73,8 +72,7 @@
   private Iterable<Artifact> inputs;
   private String langParameter;
   private String langPluginName;
-  private String langPluginParameter;
-  private Supplier<String> langPluginParameterSupplier;
+  private Supplier<String> langPluginParameter;
   private boolean hasServices;
   private Iterable<String> additionalCommandLineArguments;
   private Iterable<FilesToRunProvider> additionalTools;
@@ -100,17 +98,11 @@
     return this;
   }
 
-  public ProtoCompileActionBuilder setLangPluginParameter(String langPluginParameter) {
+  public ProtoCompileActionBuilder setLangPluginParameter(Supplier<String> langPluginParameter) {
     this.langPluginParameter = langPluginParameter;
     return this;
   }
 
-  public ProtoCompileActionBuilder setLangPluginParameterSupplier(
-      Supplier<String> langPluginParameterSupplier) {
-    this.langPluginParameterSupplier = langPluginParameterSupplier;
-    return this;
-  }
-
   public ProtoCompileActionBuilder setAdditionalCommandLineArguments(
       Iterable<String> additionalCmdLine) {
     this.additionalCommandLineArguments = additionalCmdLine;
@@ -206,10 +198,6 @@
   }
 
   public Action[] build() {
-    checkState(
-        langPluginParameter == null || langPluginParameterSupplier == null,
-        "Only one of {langPluginParameter, langPluginParameterSupplier} should be set.");
-
     if (isEmpty(outputs)) {
       return NO_ACTIONS;
     }
@@ -286,18 +274,13 @@
       }
     } else {
       FilesToRunProvider langPluginTarget = getLangPluginTarget();
-      Supplier<String> langPluginParameter1 =
-          langPluginParameter == null
-              ? langPluginParameterSupplier
-              : Suppliers.ofInstance(langPluginParameter);
-
       Preconditions.checkArgument(langParameter == null);
-      Preconditions.checkArgument(langPluginParameter1 != null);
+      Preconditions.checkArgument(langPluginParameter != null);
       // We pass a separate langPluginName as there are plugins that cannot be overridden
       // and thus we have to deal with "$xx_plugin" and "xx_plugin".
       result.addFormatted(
           "--plugin=protoc-gen-%s=%s", langPrefix, langPluginTarget.getExecutable().getExecPath());
-      result.addLazyString(new LazyLangPluginFlag(langPrefix, langPluginParameter1));
+      result.addLazyString(new LazyLangPluginFlag(langPrefix, langPluginParameter));
     }
 
     result.addAll(ruleContext.getFragment(ProtoConfiguration.class).protocOpts());