perf sampling: minimal UI for stacks as slice columns

The tracker is fairly stateless atm (and we don't yet persist the perf samples
in a table), but it felt more appropriate than putting everything in
proto_trace_parser (though that in turn diffuses the logic...).

Bug: 144281346
Change-Id: Ie2c9aeabaea757bef8c886b6a1825dc1ee1a161f
diff --git a/Android.bp b/Android.bp
index 8a9da79..5c70f53 100644
--- a/Android.bp
+++ b/Android.bp
@@ -6307,6 +6307,7 @@
     "src/trace_processor/importers/proto/track_event_parser.cc",
     "src/trace_processor/importers/proto/track_event_tokenizer.cc",
     "src/trace_processor/metadata_tracker.cc",
+    "src/trace_processor/perf_sample_tracker.cc",
     "src/trace_processor/process_tracker.cc",
     "src/trace_processor/slice_tracker.cc",
     "src/trace_processor/stack_profile_tracker.cc",