Properly support textual_hdrs.

--
MOS_MIGRATED_REVID=96400739

src/main/java/com/google/devtools/build/lib/pkgcache/SrcTargetUtil.java

diff --git a/src/main/java/com/google/devtools/build/lib/pkgcache/SrcTargetUtil.java b/src/main/java/com/google/devtools/build/lib/pkgcache/SrcTargetUtil.java
index b8f4b3e..f2d2cb8 100644
--- a/src/main/java/com/google/devtools/build/lib/pkgcache/SrcTargetUtil.java
+++ b/src/main/java/com/google/devtools/build/lib/pkgcache/SrcTargetUtil.java
@@ -66,10 +66,12 @@
   private static final ImmutableSet<String> SOURCE_ATTRIBUTES =
       ImmutableSet.of("srcs", "src", "srcjar");
 
-  // Attributes referring to "headers".
-  private static final ImmutableSet<String> HEADER_ATTRIBUTES =
-      ImmutableSet.of("hdrs", "textual_hdrs");
-  
+  // Attribute referring to "headers".
+  private static final String HEADER_ATTRIBUTE = "hdrs";
+
+  // Attribute referring to "textual headers".
+  private static final String TEXTUAL_HEADER_ATTRIBUTE = "textual_hdrs";
+
   // The attribute to search in filegroups.
   private static final ImmutableSet<String> FILEGROUP_ATTRIBUTES =
       ImmutableSet.of("srcs");
@@ -84,7 +86,8 @@
       throws NoSuchTargetException, NoSuchPackageException, InterruptedException  {
     ImmutableSet<String> srcAndHdrAttributes = ImmutableSet.<String>builder()
         .addAll(SOURCE_ATTRIBUTES)
-        .addAll(HEADER_ATTRIBUTES)
+        .add(HEADER_ATTRIBUTE)
+        .add(TEXTUAL_HEADER_ATTRIBUTE)
         .build();
     return getTargets(eventHandler, rule, srcAndHdrAttributes, Sets.newHashSet(rule), provider);
   }
@@ -93,10 +96,18 @@
   public static List<FileTarget> getHdrTargets(EventHandler eventHandler, Rule rule,
                                                      TargetProvider provider)
       throws NoSuchTargetException, NoSuchPackageException, InterruptedException  {
-    ImmutableSet<String> srcAndHdrAttributes = ImmutableSet.copyOf(HEADER_ATTRIBUTES);
-    return getTargets(eventHandler, rule, srcAndHdrAttributes, Sets.newHashSet(rule), provider);
+    return getTargets(
+        eventHandler, rule, ImmutableSet.of(HEADER_ATTRIBUTE), Sets.newHashSet(rule), provider);
   }
-  
+
+  @ThreadSafety.ThreadSafe
+  public static List<FileTarget> getTextualHdrTargets(
+      EventHandler eventHandler, Rule rule, TargetProvider provider)
+      throws NoSuchTargetException, NoSuchPackageException, InterruptedException {
+    return getTargets(eventHandler, rule, ImmutableSet.of(TEXTUAL_HEADER_ATTRIBUTE),
+        Sets.newHashSet(rule), provider);
+  }
+
   /**
    * @see #getSrcTargets(EventHandler, Rule, TargetProvider)
    */