Allow uniquifiers to throw QueryExceptions.

RELNOTES: None.
PiperOrigin-RevId: 202961077
diff --git a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
index a53f1d6..2df8008 100644
--- a/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/query2/SkyQueryEnvironment.java
@@ -600,13 +600,13 @@
 
   @Override
   public <V> MutableMap<Target, V> createMutableMap() {
-    return new MutableKeyExtractorBackedMapImpl<Target, Label, V>(TargetKeyExtractor.INSTANCE);
+    return new MutableKeyExtractorBackedMapImpl<>(TargetKeyExtractor.INSTANCE);
   }
 
   @ThreadSafe
   @Override
   public Uniquifier<Target> createUniquifier() {
-    return createTargetUniquifier();
+    return new UniquifierImpl<>(TargetKeyExtractor.INSTANCE);
   }
 
   @ThreadSafe
@@ -621,13 +621,8 @@
   }
 
   @ThreadSafe
-  Uniquifier<Target> createTargetUniquifier() {
-    return new UniquifierImpl<>(TargetKeyExtractor.INSTANCE, DEFAULT_THREAD_COUNT);
-  }
-
-  @ThreadSafe
   public Uniquifier<SkyKey> createSkyKeyUniquifier() {
-    return new UniquifierImpl<>(SkyKeyKeyExtractor.INSTANCE, DEFAULT_THREAD_COUNT);
+    return new UniquifierImpl<>(SkyKeyKeyExtractor.INSTANCE);
   }
 
   private ImmutableSet<PathFragment> getBlacklistedExcludes(TargetPatternKey targetPatternKey)
@@ -1126,8 +1121,8 @@
     // memory. We should have a threshold for when to invoke the callback with a batch, and also a
     // separate, larger, bound on the number of targets being processed at the same time.
     private final ThreadSafeOutputFormatterCallback<Target> callback;
-    private final Uniquifier<Target> uniquifier =
-        new UniquifierImpl<>(TargetKeyExtractor.INSTANCE, DEFAULT_THREAD_COUNT);
+    private final UniquifierImpl<Target, ?> uniquifier =
+        new UniquifierImpl<>(TargetKeyExtractor.INSTANCE);
     private final Object pendingLock = new Object();
     private List<Target> pending = new ArrayList<>();
     private int batchThreshold;