service: Emit a marker when all data source started

Adds a marker in the trace when the
all-data-sources-started event is hit (regardless of whether
the consumer is listening for that or not). This allows to
identify in the trace the point in time when all data sources
where recording trace data.

Bug: 150960749
Change-Id: Ic1c33a6da220d93b6f1b358b838a84b4ca076ac3
diff --git a/BUILD b/BUILD
index 922f2f0..5c65d0f 100644
--- a/BUILD
+++ b/BUILD
@@ -2342,6 +2342,7 @@
     name = "protos_perfetto_trace_perfetto_protos",
     srcs = [
         "protos/perfetto/trace/perfetto/perfetto_metatrace.proto",
+        "protos/perfetto/trace/perfetto/tracing_service_event.proto",
     ],
     visibility = [
         PERFETTO_CONFIG.proto_library_visibility,