Add histograms for ExternalDataUseObserver

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 956e217746ac596da0b6e1729336686571985104..411dec6347478351e4d2b52e11dc8dafd784d3bb 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -6453,6 +6453,60 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="DataUsage.ReportSubmission.Failed.Bytes" units="bytes">
+  <owner>bengr@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    Count of bytes in the data use reports that were submitted to the external
+    data use observer and the external data use observer reported the submission
+    as failed. Recorded every time external data use observer reports that
+    submission of data use report failed. This does not include the reports that
+    timed-out.
+  </summary>
+</histogram>
+
+<histogram name="DataUsage.ReportSubmission.Lost.Bytes" units="bytes">
+  <owner>bengr@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    Count of bytes in the data use reports that were lost before an attempt is
+    made to submit it to the external data use observer. Recorded every time a
+    report is lost before an attempt is made to submit it to the external data

[sclittle, 2015/12/08 00:36:21]

nit: What is the "external data use observer" here? The C++ one? The Java one?

[tbansal1, 2015/12/08 02:01:25]

Done.

+    use observer. A submission may be lost if the data use report could not be
+    buffered due to internal buffers being full.
+  </summary>
+</histogram>
+
+<histogram name="DataUsage.ReportSubmission.Successful.Bytes" units="bytes">
+  <owner>bengr@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    Count of bytes in the data use reports that were successfully submitted to
+    the external data use observer. Recorded every time a report is successfully

[sclittle, 2015/12/08 00:36:21]

nit: This "Recorded every time..." doesn't actually seem accurate. Isn't this
actually recorded when the Java external data use observer notifies that the
submission was a success?

Otherwise this would include the timeouts and failed reports as well.

[tbansal1, 2015/12/08 02:01:25]

Done.

+    submitted to the external data use observer.
+  </summary>
+</histogram>
+
+<histogram name="DataUsage.ReportSubmission.TimedOut.Bytes" units="bytes">
+  <owner>bengr@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    Count of bytes in the data use reports whose submission to the external data
+    use observer timed out. Recorded every time submission of a report to the
+    external data use observer times out.
+  </summary>
+</histogram>
+
+<histogram name="DataUsage.ReportSubmissionResult"
+    enum="DataUsageReportSubmissionResult">
+  <owner>bengr@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    Result of data usage report submission. Recorded every time a report is
+    submitted to the external data use observer.

[sclittle, 2015/12/08 00:36:21]

nit: What does "submitted" mean here? Maybe you could just leave out the
"Recorded every time..." sentence.

[tbansal1, 2015/12/08 02:01:25]

Done.

+  </summary>
+</histogram>
+
 <histogram name="DataUse.MessageSize" units="bytes">
   <owner>amohammadkhan@chromium.org</owner>
   <owner>bengr@chromium.org</owner>
@@ -58334,6 +58388,13 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="10" label="Diabled directly from the First Run Experience"/>
 </enum>
 
+<enum name="DataUsageReportSubmissionResult" type="int">
+  <int value="0" label="Successful"/>
+  <int value="1" label="Failed"/>
+  <int value="2" label="Timed out"/>
+  <int value="3" label="Lost"/>
+</enum>
+
 <enum name="DataUseServices" type="int">
   <int value="0" label="Not Tagged"/>
   <int value="1" label="Suggestions"/>