Remove unnecessary env.valuesMissing() call.

--
MOS_MIGRATED_REVID=103975426

src/main/java/com/google/devtools/build/lib/skyframe/RecursiveDirectoryTraversalFunction.java

@@ -104,9 +104,8 @@ interface Visitor {
    * by {@link #aggregateWithSubdirectorySkyValues}, and returns that aggregation.
    *
    * <p>Returns null if {@code env.valuesMissing()} is true, checked after each call to one of
-   * {@link RecursiveDirectoryTraversalFunction}'s abstract methods except for {@link
-   * #getEmptyReturn}. (And after each of {@code visitDirectory}'s own uses of {@code env}, of
-   * course.)
+   * {@link RecursiveDirectoryTraversalFunction}'s abstract methods that were given {@code env}.
+   * (And after each of {@code visitDirectory}'s own uses of {@code env}, of course.)
    */
   TReturn visitDirectory(RecursivePkgKey recursivePkgKey, Environment env) {
     RootedPath rootedPath = recursivePkgKey.getRootedPath();
@@ -151,10 +150,6 @@ TReturn visitDirectory(RecursivePkgKey recursivePkgKey, Environment env) {
     }
 
     TVisitor visitor = getInitialVisitor();
-    if (env.valuesMissing()) {
-      return null;
-    }
-
     if (pkgLookupValue.packageExists()) {
       if (pkgLookupValue.getRoot().equals(root)) {
         Package pkg = null;
@@ -252,19 +247,12 @@ TReturn visitDirectory(RecursivePkgKey recursivePkgKey, Environment env) {
       RootedPath subdirectoryRootedPath = RootedPath.toRootedPath(root, subdirectory);
       childDeps.add(getSkyKeyForSubdirectory(recursivePkgKey.getRepository(),
           subdirectoryRootedPath, excludedSubdirectoriesBeneathThisSubdirectory));
-      if (env.valuesMissing()) {
-        return null;
-      }
     }
     Map<SkyKey, SkyValue> subdirectorySkyValues = env.getValues(childDeps);
     if (env.valuesMissing()) {
       return null;
     }
-    TReturn aggregation = aggregateWithSubdirectorySkyValues(visitor, subdirectorySkyValues);
-    if (env.valuesMissing()) {
-      return null;
-    }
-    return aggregation;
+    return aggregateWithSubdirectorySkyValues(visitor, subdirectorySkyValues);
   }
 
   // Ignore all errors in traversal and return an empty value.