Add prefix to logs based on call source

Bug: 144166111
Test: manual, ./external/chromium-trace/systrace.py camera -o
/tmp/mytrace.html (after changing tracing tag to "camera" since it isn't
used for anything else in automotive)

Change-Id: I082888daee17c671ba9ab5c8cf1ae486e683ab16
diff --git a/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java b/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java
index 48127a7..8d4a2cd 100644
--- a/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java
+++ b/packages/SystemUI/src/com/android/systemui/SystemUIApplication.java
@@ -142,7 +142,7 @@
 
     public void startServicesIfNeeded() {
         String[] names = getResources().getStringArray(R.array.config_systemUIServiceComponents);
-        startServicesIfNeeded(names);
+        startServicesIfNeeded(/* metricsPrefix= */ "StartServices", names);
     }
 
     /**
@@ -154,10 +154,10 @@
     void startSecondaryUserServicesIfNeeded() {
         String[] names =
                   getResources().getStringArray(R.array.config_systemUIServiceComponentsPerUser);
-        startServicesIfNeeded(names);
+        startServicesIfNeeded(/* metricsPrefix= */ "StartSecondaryServices", names);
     }
 
-    private void startServicesIfNeeded(String[] services) {
+    private void startServicesIfNeeded(String metricsPrefix, String[] services) {
         if (mServicesStarted) {
             return;
         }
@@ -178,12 +178,12 @@
                 Process.myUserHandle().getIdentifier() + ".");
         TimingsTraceLog log = new TimingsTraceLog("SystemUIBootTiming",
                 Trace.TRACE_TAG_APP);
-        log.traceBegin("StartServices");
+        log.traceBegin(metricsPrefix);
         final int N = services.length;
         for (int i = 0; i < N; i++) {
             String clsName = services[i];
             if (DEBUG) Log.d(TAG, "loading: " + clsName);
-            log.traceBegin("StartServices" + clsName);
+            log.traceBegin(metricsPrefix + clsName);
             long ti = System.currentTimeMillis();
             Class cls;
             try {