Adding logging of perf data type and adding error messaging

Change-Id: I349768cec84b3545ca35f8836fdbd83fda6c2bc2
Reviewed-on: https://chromium-review.googlesource.com/1054193Reviewed-by: Simon Hatch <simonhatch@chromium.org>
Commit-Queue: Emily Hanley <eyaich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557602}

tools/perf/core/results_dashboard.py

@@ -130,7 +130,6 @@ def _SendResultsFromCache(cache_file_name, url, oauth_token):
     line = line.strip()
     if not line:
       continue
-    print 'Sending result %d of %d to dashboard.' % (index + 1, total_results)
     # We need to check whether we're trying to upload histograms. If the JSON
     # is invalid, we should not try to send this data or re-try it later.
     # Instead, we'll print an error.
@@ -141,6 +140,8 @@ def _SendResultsFromCache(cache_file_name, url, oauth_token):
       continue
 
     data_type = ('histogram' if is_histogramset else 'chartjson')
+    print 'Sending %s result %d of %d to dashboard.' % (
+        data_type, index + 1, total_results)
 
     try:
       if is_histogramset:
@@ -490,7 +491,7 @@ def _SendResultsJson(url, results_json):
       # If the remote app rejects the JSON, it's probably malformed,
       # so we don't want to retry it.
       raise SendResultsFatalException('Discarding JSON, error:\n%s' % error)
-    raise SendResultsRetryException()
+    raise SendResultsRetryException(error)
 
 def _Httplib2Request(url, data, oauth_token):
   data = zlib.compress(data)