Distinguish systrace timelines for playback and capture

Bug: 30120068
Change-Id: If416540f0785e83e7b1e8ba986ee55b5b9298a2a
diff --git a/services/audioflinger/FastThread.h b/services/audioflinger/FastThread.h
index 2efb6de..816b666 100644
--- a/services/audioflinger/FastThread.h
+++ b/services/audioflinger/FastThread.h
@@ -30,7 +30,7 @@
 class FastThread : public Thread {
 
 public:
-            FastThread();
+            FastThread(const char *cycleMs, const char *loadUs);
     virtual ~FastThread();
 
 private:
@@ -88,6 +88,9 @@
     FastThreadState::Command mCommand;
     bool            mAttemptedWrite;
 
+    char            mCycleMs[16];   // cycle_ms + suffix
+    char            mLoadUs[16];    // load_us + suffix
+
 };  // class FastThread
 
 }   // android