Dump the transition type in always on transition trace

Required by FaaS to better detect custom transitions

Bug: 270951098
Test: atest FlickerLibTest
Change-Id: I9e7a4a4c6cd44d2fb7aa0014ded8ab38dc694d03

core/proto/android/server/windowmanagertransitiontrace.proto

@@ -53,7 +53,8 @@ message Transition {
   required int64 create_time_ns = 4;
   required int64 send_time_ns = 5;
   optional int64 finish_time_ns = 6; // consider aborted if not provided
-  repeated Target targets = 7;
+  required int32 type = 7;
+  repeated Target targets = 8;
 }
 
 message Target {

services/core/java/com/android/server/wm/TransitionTracer.java

@@ -146,6 +146,8 @@ public class TransitionTracer {
                     transition.getSyncId());
         }
 
+        outputStream.write(com.android.server.wm.shell.Transition.TYPE, transition.mType);
+
         for (int i = 0; i < targets.size(); ++i) {
             final long changeToken = outputStream
                     .start(com.android.server.wm.shell.Transition.TARGETS);