Allow traced to create files within /data/misc/perfetto-traces

Together with aosp/1282157 this change allows the service to
create trace files in the /data/misc/perfetto-traces folder.
Before this change they needed to be created by the perfetto
cmdline client and pass the FD.
This doesn't work for host tools like Android GPU Inspector
(https://gpuinspector.dev/) which talk to the UNIX socket
over adb forward and cannot pass a FD from the host.

Bug: 153519149
Test: manual: adb shell perfetto --txt -c -
  buffers { size_kb: 65536 }
  data_sources {
    config {
      name: "linux.ftrace"
      ftrace_config { ftrace_events: "sched_switch" }
    }
  }
  duration_ms: 5000
  write_into_file: true
  output_path: "/data/misc/perfetto-traces/ttt"

Change-Id: I184329805741654983843e6a29c1fac19a836f59
1 file changed