Introduce a Builder class for creating instances of ConfiguredTargetKey.

Part of work on toolchain transitions, #10523.

PiperOrigin-RevId: 313615963
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/AspectValueKey.java b/src/main/java/com/google/devtools/build/lib/skyframe/AspectValueKey.java
index d14b5a4..5aaf08e 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/AspectValueKey.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/AspectValueKey.java
@@ -267,7 +267,10 @@
       }
 
       return createAspectKey(
-          ConfiguredTargetKey.of(label, baseConfiguredTargetKey.getConfigurationKey()),
+          ConfiguredTargetKey.builder()
+              .setLabel(label)
+              .setConfigurationKey(baseConfiguredTargetKey.getConfigurationKey())
+              .build(),
           newBaseKeys.build(),
           aspectDescriptor,
           aspectConfigurationKey);