Add a timeout option in shell subscriber.

Test: cts added
Change-Id: I0fe854fcfd5535ed03e502a4cad3f57079b45381
diff --git a/cmds/statsd/src/StatsService.cpp b/cmds/statsd/src/StatsService.cpp
index f2a4663..3107b4d 100644
--- a/cmds/statsd/src/StatsService.cpp
+++ b/cmds/statsd/src/StatsService.cpp
@@ -360,7 +360,11 @@
             if (mShellSubscriber == nullptr) {
                 mShellSubscriber = new ShellSubscriber(mUidMap, mPullerManager);
             }
-            mShellSubscriber->startNewSubscription(in, out, resultReceiver);
+            int timeoutSec = -1;
+            if (argCount >= 2) {
+                timeoutSec = atoi(args[1].c_str());
+            }
+            mShellSubscriber->startNewSubscription(in, out, resultReceiver, timeoutSec);
             return NO_ERROR;
         }
     }