Rename Root to ArtifactRoot.

This is slightly more descriptive, and we will potentially want to use the name Root for a broader concept shared between ArtifactRoot and RootedPath.

PiperOrigin-RevId: 182082367
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java
index aba2931..339ad4e 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java
@@ -31,8 +31,8 @@
 import com.google.devtools.build.lib.actions.Artifact.SpecialArtifact;
 import com.google.devtools.build.lib.actions.Artifact.SpecialArtifactType;
 import com.google.devtools.build.lib.actions.Artifact.TreeFileArtifact;
+import com.google.devtools.build.lib.actions.ArtifactRoot;
 import com.google.devtools.build.lib.actions.MissingInputFileException;
-import com.google.devtools.build.lib.actions.Root;
 import com.google.devtools.build.lib.actions.util.ActionsTestUtil;
 import com.google.devtools.build.lib.actions.util.TestAction.DummyAction;
 import com.google.devtools.build.lib.events.NullEventHandler;
@@ -245,7 +245,7 @@
   }
 
   private Artifact createSourceArtifact(String path) {
-    return new Artifact(PathFragment.create(path), Root.asSourceRoot(root));
+    return new Artifact(PathFragment.create(path), ArtifactRoot.asSourceRoot(root));
   }
 
   private Artifact createDerivedArtifact(String path) {
@@ -253,13 +253,17 @@
     Path fullPath = root.getRelative(execPath);
     Artifact output =
         new Artifact(
-            fullPath, Root.asDerivedRoot(root, root.getRelative("out")), execPath, ALL_OWNER);
+            fullPath,
+            ArtifactRoot.asDerivedRoot(root, root.getRelative("out")),
+            execPath,
+            ALL_OWNER);
     actions.add(new DummyAction(ImmutableList.<Artifact>of(), output));
     return output;
   }
 
   private Artifact createMiddlemanArtifact(String path) {
-    Root middlemanRoot = Root.middlemanRoot(middlemanPath, middlemanPath.getRelative("out"));
+    ArtifactRoot middlemanRoot =
+        ArtifactRoot.middlemanRoot(middlemanPath, middlemanPath.getRelative("out"));
     Path fullPath = middlemanRoot.getPath().getRelative(path);
     return new Artifact(
         fullPath, middlemanRoot, fullPath.relativeTo(middlemanRoot.getExecRoot()), ALL_OWNER);
@@ -276,7 +280,7 @@
     Path fullPath = root.getRelative(execPath);
     return new SpecialArtifact(
         fullPath,
-        Root.asDerivedRoot(root, root.getRelative("out")),
+        ArtifactRoot.asDerivedRoot(root, root.getRelative("out")),
         execPath,
         ALL_OWNER,
         SpecialArtifactType.TREE);