Revert of Optimize JSON dump in telemetry.

telemetry/telemetry/value/trace.py

Index: telemetry/telemetry/value/trace.py
diff --git a/telemetry/telemetry/value/trace.py b/telemetry/telemetry/value/trace.py
index 1104ce9a8ecc2005bc9a9d95629e6bc845f44380..df2113bf17d4d2414deef5495d8104b923b8e0eb 100644
--- a/telemetry/telemetry/value/trace.py
+++ b/telemetry/telemetry/value/trace.py
@@ -49,9 +49,7 @@
       if isinstance(trace, basestring):
         fp.write(trace)
       elif isinstance(trace, dict) or isinstance(trace, list):
-        # Creating the string using dumps and then writing it is
-        # ~5x faster than using json.dump().
-        fp.write(json.dumps(trace))
+        json.dump(trace, fp)
       else:
         raise TypeError('Trace is of unknown type.')