feat: Support imports in declarative API

Bug: b/414425806
Change-Id: I7c5ac2937b4557812fd7d4663b2c0b004d95b044
GitOrigin-RevId: c078b3310ace966155757a3ce078f85132deaaa4

Author: Privacy Sandbox Team

apis/privacysandbox/apis/roma/app_api/v1/options.proto

@@ -63,6 +63,8 @@ message RomaServiceAnnotation {
   // cpp_host_process_callback_includes would contain
   // `foo/bar/foobar_native_functions.h`.
   repeated string cpp_host_process_callback_includes = 6;
+  // import strings for the generate protobuf spec
+  repeated string proto_imports = 9;
 }
 
 message RomaFunctionAnnotation {

src/roma/tools/api_plugin/roma_api.bzl

@@ -995,6 +995,7 @@ def roma_byob_sdk(
         exclude_tools = False,
         guide_intro_text = _default_guide_intro,
         generated_proto_path = "",
+        proto_deps = [],
         **kwargs):
     """
     Top-level macro for the Roma BYOB SDK.
@@ -1030,6 +1031,7 @@ def roma_byob_sdk(
     proto_library(
         name = name + "_proto",
         srcs = [":{}.proto".format(name)],
+        deps = proto_deps,
     )
     cc_proto_library(
         name = name + "_cc_proto",

src/roma/tools/api_plugin/tmpl/byob/app/udf_interface.proto.tmpl

@@ -35,6 +35,9 @@ package {{$svcopts.CppNamespace | replace "::" "." }};
 {{ if len $svcopts.CsharpNamespace }}option csharp_namespace = "{{ $svcopts.CsharpNamespace }}";{{ end }}
 {{ if len $svcopts.GoPackage }}option go_package = "{{ $svcopts.GoPackage }}";{{ end }}
 
+{{- range $import := $svcopts.ProtoImports}}
+import "{{$import}}";
+{{- end}}
 
 {{- range $rpc := $svc.MethodsWithOption "privacysandbox.apis.roma.app_api.v1.roma_rpc_annotation"}}
 {{- $rpcopts := index $rpc.Options "privacysandbox.apis.roma.app_api.v1.roma_rpc_annotation" }}