simpleperf: add magic and version in report-sample protobuf output file.
Also set default protobuf output file to report_sample.trace.
Bug: http://b/74527012
Bug: http://b/77652949
Test: run simpleperf_unit_test.
Change-Id: Ibe4b1c7f2c7d7d743b0c0c6cb9b3772b59e8bf4a
diff --git a/simpleperf/report_sample.proto b/simpleperf/report_sample.proto
index 5d4c3ac..a6612a9 100644
--- a/simpleperf/report_sample.proto
+++ b/simpleperf/report_sample.proto
@@ -1,4 +1,6 @@
// The file format generated by report_sample.proto is as below:
+// char magic[10] = "SIMPLEPERF";
+// LittleEndian16(version) = 1;
// LittleEndian32(record_size_0)
// message Record(record_0) (having record_size_0 bytes)
// LittleEndian32(record_size_1)