Return SDK deps as additional proto field

BUG=None
TEST=manually ran endpoint

Change-Id: Ia177a37bda28d8d9e7005c862ad6a6ef753864e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1931294
Tested-by: Chris McDonald <cjmcdonald@chromium.org>
Reviewed-by: Sean Abraham <seanabraham@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/dependency.py b/api/controller/dependency.py
index 072175d..5ad5bc7 100644
--- a/api/controller/dependency.py
+++ b/api/controller/dependency.py
@@ -68,5 +68,6 @@
   """
   board = input_proto.build_target.name
 
-  json_map = dependency.GetBuildDependency(board)
+  json_map, sdk_json_map = dependency.GetBuildDependency(board)
   AugmentDepGraphProtoFromJsonMap(json_map, output_proto.dep_graph)
+  AugmentDepGraphProtoFromJsonMap(sdk_json_map, output_proto.sdk_dep_graph)