Support AutoValue annotation processors via exported_deps

Change-Id: I9ca9cde74c9f080c64f32810545576bb486dfaaf
diff --git a/tools/default.defs b/tools/default.defs
index 30518c4..8dac3e5 100644
--- a/tools/default.defs
+++ b/tools/default.defs
@@ -63,7 +63,8 @@
     kwargs[apdk] = []
   apds = kwargs.get(apdk, [])
 
-  if AUTO_VALUE_DEP in kwargs.get('deps', []):
+  all_deps = kwargs.get('deps', []) + kwargs.get('exported_deps', [])
+  if AUTO_VALUE_DEP in all_deps:
     aps.extend(AUTO_VALUE_PROCESSORS)
     apds.extend(AUTO_VALUE_PROCESSOR_DEPS)