Clean up API for the Extension class

RELNOTES: None
PiperOrigin-RevId: 155507750
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/AspectFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/AspectFunction.java
index 52d00e3..5569a64 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/AspectFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/AspectFunction.java
@@ -116,7 +116,7 @@
         return null;
       }
 
-      Object skylarkValue = skylarkImportLookupValue.getEnvironmentExtension()
+      Object skylarkValue = skylarkImportLookupValue.getEnvironmentExtension().getBindings()
           .get(skylarkValueName);
       if (!(skylarkValue instanceof SkylarkAspect)) {
         throw new ConversionException(