Merge "Bazel: Force sourcemaps inlining in polymer bundler" into stable-2.16

tools/bzl/js.bzl

diff --git a/tools/bzl/js.bzl b/tools/bzl/js.bzl
index e6c4870..8184d75 100644
--- a/tools/bzl/js.bzl
+++ b/tools/bzl/js.bzl
@@ -316,6 +316,7 @@
         "$p/" + ctx.file._bundler_archive.path,
         "--inline-scripts",
         "--inline-css",
+        "--sourcemaps",
         "--strip-comments",
         "--out-file",
         "$p/" + bundled.path,