Add Metrics about Uploading UMA Records from Previous Sessions

Change-Id: I908a337129062e882b185a08329fecfd7db6c496
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2504593Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822037}

components/metrics/unsent_log_store.cc

@@ -162,6 +162,7 @@ void UnsentLogStore::MarkStagedLogAsSent() {
   DCHECK_LT(static_cast<size_t>(staged_log_index_), list_.size());
   if (list_[staged_log_index_]->samples_count.has_value())
     total_samples_sent_ += list_[staged_log_index_]->samples_count.value();
+  metrics_->RecordSentLog();
 }
 
 void UnsentLogStore::TrimAndPersistUnsentLogs() {
@@ -303,6 +304,7 @@ void UnsentLogStore::TrimLogs() {
   size_t dropped_logs_count = list_.size() - trimmed_list.size();
   if (dropped_logs_count > 0)
     metrics_->RecordDroppedLogsNum(dropped_logs_count);
+  metrics_->RecordIntendingToSentLogs(trimmed_list.size());
 
   // Put the trimmed list in the correct place.
   list_.swap(trimmed_list);

components/metrics/unsent_log_store_metrics.cc

@@ -22,6 +22,10 @@ void UnsentLogStoreMetrics::RecordDroppedLogSize(size_t size) {}
 
 void UnsentLogStoreMetrics::RecordDroppedLogsNum(int dropped_logs_num) {}
 
+void UnsentLogStoreMetrics::RecordIntendingToSentLogs(int num) {}
+
+void UnsentLogStoreMetrics::RecordSentLog() {}
+
 void UnsentLogStoreMetrics::RecordLastUnsentLogMetadataMetrics(
     int unsent_samples_count,
     int sent_samples_count,

components/metrics/unsent_log_store_metrics.h

@@ -40,10 +40,21 @@ class UnsentLogStoreMetrics {
   virtual void RecordCompressionRatio(size_t compressed_size,
                                       size_t original_size);
 
+  // Records the size of a dropped log in bytes.
   virtual void RecordDroppedLogSize(size_t size);
 
+  // Record the number of logs that were dropped (not staged).  These include
+  // logs that were dropped due to be being too large and also logs that were
+  // dropped because there were too many.
   virtual void RecordDroppedLogsNum(int dropped_logs_num);
 
+  // Records the number of logs that were not dropped and instead staged /
+  // intended to be sent.
+  virtual void RecordIntendingToSentLogs(int num);
+
+  // Record when a single staged log was sent.
+  virtual void RecordSentLog();
+
   virtual void RecordLastUnsentLogMetadataMetrics(int unsent_samples_count,
                                                   int sent_samples_count,
                                                   int persisted_size_in_kb);

components/metrics/unsent_log_store_metrics_impl.cc

@@ -31,6 +31,14 @@ void UnsentLogStoreMetricsImpl::RecordDroppedLogsNum(int dropped_logs_num) {
   base::UmaHistogramCounts1M("UMA.UnsentLogs.Dropped", dropped_logs_num);
 }
 
+void RecordIntendingToSentLogs(int num) {
+  base::UmaHistogramExactLinear("UMA.UnsentLogs.IntendingToSend", num, 22);
+}
+
+void RecordSentLog() {
+  base::UmaHistogramBoolean("UMA.UnsentLogs.Sent", true);
+}
+
 void UnsentLogStoreMetricsImpl::RecordLastUnsentLogMetadataMetrics(
     int unsent_samples_count,
     int sent_samples_count,

tools/metrics/histograms/histograms_xml/uma/histograms.xml

@@ -584,9 +584,13 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
     expires_after="2021-08-30">
   <owner>holte@chromium.org</owner>
   <owner>asvitkine@chromium.org</owner>
+  <owner>mpearson@chromium.org</owner>
   <owner>src/base/metrics/OWNERS</owner>
   <summary>
-    Counter for number of UMA unsent logs removed from persistent storage.
+    The number of UMA unsent logs removed from persistent storage.
+
+    Useful in comparison with UMA.UnsentLogs.IntendingToSend (that counts hte
+    number of UMA unsent logs that are intended to be sent, i.e., not dropped).
   </summary>
 </histogram>
 
@@ -604,6 +608,20 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="UMA.UnsentLogs.IntendingToSend" units="logs"
+    expires_after="2021-04-01">
+  <owner>mpearson@chromium.org</owner>
+  <owner>src/base/metrics/OWNERS</owner>
+  <summary>
+    The number of UMA unsent logs from persistent storage that will be staged /
+    are intended to be sent. These logs are not dropped from persistent storage.
+
+    Useful in comparison with UMA.UnsentLogs.Dropped (to see how many persistent
+    logs are intended to be sent versus are not intended to be sent) and with
+    UMA.UnsentLogs.IntendingToSend (to see how many are actually sent).
+  </summary>
+</histogram>
+
 <histogram name="UMA.UnsentLogs.PersistedSizeInKB" units="KB"
     expires_after="2021-05-30">
   <owner>michaelbai@chromium.org</owner>
@@ -616,6 +634,17 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="UMA.UnsentLogs.Sent" enum="Boolean" expires_after="2021-04-01">
+  <owner>mpearson@chromium.org</owner>
+  <owner>src/base/metrics/OWNERS</owner>
+  <summary>
+    Emitted when a UMA unsent log is marked as sent.
+
+    Useful in comparison with UMA.UnsentLogs.Dropped and
+    UMA.UnsentLogs.IntendingToSend.
+  </summary>
+</histogram>
+
 <histogram name="UMA.UnsentLogs.SentCount" units="samples"
     expires_after="2021-05-30">
   <owner>michaelbai@chromium.org</owner>