Reland: Build Mojo apps in sub-dirs, like application packages.

mojo/runner/BUILD.gn

Index: mojo/runner/BUILD.gn
diff --git a/mojo/runner/BUILD.gn b/mojo/runner/BUILD.gn
index 6566bbc924ff066b456baa293e3b9857c6eea2d1..45a88468c807aa1aa24b933f87dad6897b5f0d69 100644
--- a/mojo/runner/BUILD.gn
+++ b/mojo/runner/BUILD.gn
@@ -289,9 +289,12 @@ if (is_android) {
     ]
     sources = [
       "$root_out_dir/lib.stripped/libbootstrap.so",
-      "$root_out_dir/network_service.mojo",
       "$root_out_dir/obj/mojo/runner/bootstrap_java.dex.jar",
     ]
+
+    # Directories can't be specified as sources so pass manually to the script.
+    args = [ "--files=" +
+             rebase_path("$root_out_dir/network_service", root_build_dir) ]
   }
 
   generate_mojo_shell_assets_list("build_mojo_runner_assets") {
@@ -316,14 +319,17 @@ if (is_android) {
   copy_ex("copy_mojo_runner_test_assets") {
     clear_dir = true
     dest = mojo_runner_test_assets_dir
-    sources = [
-      "$root_out_dir/test_app.mojo",
-      "$root_out_dir/test_request_tracker_app.mojo",
-    ]
     deps = [
       "//mojo/services/test_service:test_app",
       "//mojo/services/test_service:test_request_tracker_app",
     ]
+
+    # Directories can't be specified as sources so pass manually to the script.
+    args = [
+      "--files=" + rebase_path("$root_out_dir/test_app", root_build_dir),
+      "--files=" +
+          rebase_path("$root_out_dir/test_request_tracker_app", root_build_dir),
+    ]
   }
 
   android_apk("mojo_runner_apk") {