Trace Redaction - Add synth threads to process tree

In order to support thread merging, the new threads must be added to
the process tree. These ensure the threads appear in the UI correctly.

To support this, the process tree primitive has been re-implemented
using the same strategy pattern used elsewhere. There are two
extensions points, allowing:

  1. filter process
  2. filter thread
  3. add processes
  4. add threads

Bug: 336807771
Change-Id: I1291fde00ce0c15f89ed78e7425a0c9f9bc40555
diff --git a/Android.bp b/Android.bp
index d807b27..487e4dc 100644
--- a/Android.bp
+++ b/Android.bp
@@ -13618,11 +13618,11 @@
         "src/trace_redaction/prune_package_list.cc",
         "src/trace_redaction/redact_ftrace_event.cc",
         "src/trace_redaction/redact_process_events.cc",
+        "src/trace_redaction/redact_process_trees.cc",
         "src/trace_redaction/redact_sched_events.cc",
         "src/trace_redaction/remap_scheduling_events.cc",
         "src/trace_redaction/scrub_ftrace_events.cc",
         "src/trace_redaction/scrub_process_stats.cc",
-        "src/trace_redaction/scrub_process_trees.cc",
         "src/trace_redaction/scrub_trace_packet.cc",
         "src/trace_redaction/suspend_resume.cc",
         "src/trace_redaction/trace_redaction_framework.cc",