Rename ActionExecutionValue#createSimpleFileArtifactValue and make it an instance method.

The name of the method is misleading because it doesn't create anything new, just gets it from a map. It also asserts that it exists, so rename it to getExistingFileArtifactValue.

Also, make it an instance method. A static method that requires passing in an instance of the class seems awkward.

RELNOTES: None.
PiperOrigin-RevId: 312712401
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java b/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java
index 9e15389..9c7a570 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java
@@ -22,6 +22,8 @@
 import com.google.devtools.build.lib.actions.ActionLookupValue;
 import com.google.devtools.build.lib.actions.ActionLookupValue.ActionLookupKey;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.Artifact.DerivedArtifact;
+import com.google.devtools.build.lib.actions.Artifact.SpecialArtifact;
 import com.google.devtools.build.lib.actions.FileArtifactValue;
 import com.google.devtools.build.lib.actions.FilesetOutputSymlink;
 import com.google.devtools.build.lib.analysis.actions.SymlinkAction;
@@ -51,7 +53,7 @@
         inputMap.put(artifact, entry.second, /*depOwner=*/ key);
         if (artifact.isFileset()) {
           ImmutableList<FilesetOutputSymlink> expandedFileset =
-              getFilesets(env, (Artifact.SpecialArtifact) artifact);
+              getFilesets(env, (SpecialArtifact) artifact);
           if (expandedFileset != null) {
             filesetsInsideRunfiles.put(artifact, expandedFileset);
           }
@@ -87,11 +89,10 @@
     } else if (value instanceof ActionExecutionValue) {
       inputMap.put(
           key,
-          ActionExecutionValue.createSimpleFileArtifactValue(
-              (Artifact.DerivedArtifact) key, (ActionExecutionValue) value),
+          ((ActionExecutionValue) value).getExistingFileArtifactValue((DerivedArtifact) key),
           key);
       if (key.isFileset()) {
-        topLevelFilesets.put(key, getFilesets(env, (Artifact.SpecialArtifact) key));
+        topLevelFilesets.put(key, getFilesets(env, (SpecialArtifact) key));
       }
     } else {
       Preconditions.checkState(value instanceof FileArtifactValue);
@@ -100,7 +101,7 @@
   }
 
   static ImmutableList<FilesetOutputSymlink> getFilesets(
-      Environment env, Artifact.SpecialArtifact actionInput) throws InterruptedException {
+      Environment env, SpecialArtifact actionInput) throws InterruptedException {
     Preconditions.checkState(actionInput.isFileset(), actionInput);
     ActionLookupData generatingActionKey = actionInput.getGeneratingActionKey();
     ActionLookupKey filesetActionLookupKey = generatingActionKey.getActionLookupKey();
@@ -113,8 +114,8 @@
     ActionLookupData filesetActionKey;
 
     if (generatingAction instanceof SymlinkAction) {
-      Artifact.DerivedArtifact outputManifest =
-          (Artifact.DerivedArtifact) generatingAction.getInputs().getSingleton();
+      DerivedArtifact outputManifest =
+          (DerivedArtifact) generatingAction.getInputs().getSingleton();
       ActionLookupData manifestGeneratingKey = outputManifest.getGeneratingActionKey();
       Preconditions.checkState(
           manifestGeneratingKey.getActionLookupKey().equals(filesetActionLookupKey),
@@ -125,8 +126,8 @@
           manifestGeneratingKey);
       ActionAnalysisMetadata symlinkTreeAction =
           filesetActionLookupValue.getAction(manifestGeneratingKey.getActionIndex());
-      Artifact.DerivedArtifact inputManifest =
-          (Artifact.DerivedArtifact) symlinkTreeAction.getInputs().getSingleton();
+      DerivedArtifact inputManifest =
+          (DerivedArtifact) symlinkTreeAction.getInputs().getSingleton();
       ActionLookupData inputManifestGeneratingKey = inputManifest.getGeneratingActionKey();
       Preconditions.checkState(
           inputManifestGeneratingKey.getActionLookupKey().equals(filesetActionLookupKey),