ConcurrentModificationException in Tracker.zza()

[GoogleCodeExporter]

Name of affected component: Mobile Tracking

Name of related library and version: Android, Play Services Analytics 7.0.0

Issue summary:
Reporting fails sometimes when done in the service method 
WearableListenerService.onMessageReceived(). The following call causes the 
exception:
tracker.send(eventBuilder.build());

Steps to reproduce issue:
Not reproducible, seen on crash reporting tool.

Expected output:
Event sent to Google Analytics

Actual results:
java.util.ConcurrentModificationException
       at java.util.HashMap$HashIterator.nextEntry(HashMap.java:806)
       at java.util.HashMap$EntryIterator.next(HashMap.java:843)
       at java.util.HashMap$EntryIterator.next(HashMap.java:841)
       at java.util.AbstractMap.putAll(AbstractMap.java:380)
       at java.util.HashMap.putAll(HashMap.java:522)
       at com.google.android.gms.analytics.Tracker.zza()
       at mypackage.WearDataListenerService.onMessageReceived(WearDataListenerService.java)
       at com.google.android.gms.wearable.WearableListenerService$zza$2.run()
       at android.os.Handler.handleCallback(Handler.java:733)

Notes:
The Tracker is shared between multiple classes/threads as described here:
https://developers.google.com/analytics/devguides/collection/android/v4/
Due to the examples I consider it as thread safe.

Original issue reported on code.google.com by peter.ro...@gmail.com on 5 Jul 2015 at 2:27