Reformat all gn files in /tools/perf/contrib/media_router_benchmarks.

`gn format` recently changed its formatting behavior
for deps, source, and a few other elements when they
are assigned (with =) single-element lists to be consistent
with the formatting of updates (with +=) with single-element.

Now that we've rolled in a GN binary with the change,
reformat all files so that people don't get presubmit
warnings due to this.

This CL was uploaded by git cl split.

R=cliffordcheng@chromium.org

Bug: 1041419
Change-Id: I29d396de609e7884b440204a3b04212507363c96
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1998636
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#731945}

tools/perf/contrib/media_router_benchmarks/BUILD.gn

@@ -7,7 +7,6 @@ copy("telemetry_extension_resources") {
     "extension/manifest.json",
     "extension/script.js",
   ]
-  outputs = [
-    "$root_out_dir/media_router/telemetry_extension/{{source_file_part}}",
-  ]
+  outputs =
+      [ "$root_out_dir/media_router/telemetry_extension/{{source_file_part}}" ]
 }