Provide a convenience for logging types that don't have an operator<<.

Change-Id: I650b852ded67576dc5ec7c8e57732cfb49f1ecd6
diff --git a/src/thread.h b/src/thread.h
index 975edfc..ac97ebe 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -180,7 +180,7 @@
   static Thread* FromManagedThread(JNIEnv* env, jobject thread);
   static uint32_t LockOwnerFromThreadLock(Object* thread_lock);
 
-  void Dump(std::ostream& os) const;
+  void Dump(std::ostream& os, bool dump_pending_exception = false) const;
 
   State GetState() const {
     return state_;