Reducing synchronization in TraceControlHandler

Summary: Currently `TraceControlHandler` contains a lot of synchronization even from a single threaded execution context.

Reviewed By: BurntBrunch

Differential Revision: D18634346

fbshipit-source-id: eb9aae0f32e3960fa5f588df18a8403d016fb1af

java/main/com/facebook/profilo/core/TraceControlHandler.java

@@ -106,17 +106,19 @@ protected synchronized void stopTrace(TraceContext context) {
             ProfiloConstants.TRACE_CONFIG_PARAM_POST_TRACE_EXTENSION_MSEC_DEFAULT));
   }
 
-  protected synchronized void endTrace(TraceContext context) {
+  protected void endTrace(TraceContext context) {
     // This also runs teardown for all providers
     if (mListener != null) {
       mListener.onTraceStop(context);
     }
     Logger.postCloseTrace(context.traceId);
   }
 
-  protected synchronized void abortTrace(TraceContext context) {
+  protected void abortTrace(TraceContext context) {
     // stop any timeout timer associated with the thread
-    removeMessages(MSG_TIMEOUT_TRACE, context);
+    synchronized (this) {
+      removeMessages(MSG_TIMEOUT_TRACE, context);
+    }
     if (mListener != null) {
       mListener.onTraceAbort(context);
     }
@@ -130,7 +132,7 @@ protected static void timeoutTrace(long traceId) {
     control.timeoutTrace(traceId);
   }
 
-  protected synchronized void startTraceAsync(TraceContext context) {
+  protected void startTraceAsync(TraceContext context) {
     if (LogLevel.LOG_DEBUG_MESSAGE) {
       Log.d(
           LOG_TAG,