Refactoring: makes the code simpler by deleting Metadata and InputArtifactData.

(minor) ActionFS now implements MetadataProvider.getInput

PiperOrigin-RevId: 199575194
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java
index dc04d4b..53b1cec 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/FileFunction.java
@@ -19,6 +19,9 @@
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Sets;
 import com.google.devtools.build.lib.actions.FileStateType;
+import com.google.devtools.build.lib.actions.FileStateValue;
+import com.google.devtools.build.lib.actions.FileValue;
+import com.google.devtools.build.lib.actions.InconsistentFilesystemException;
 import com.google.devtools.build.lib.pkgcache.PathPackageLocator;
 import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.vfs.Path;