Add new UMA stats to get a handle on Downloads UI Usage

content/browser/download/download_stats.cc

Index: content/browser/download/download_stats.cc
diff --git a/content/browser/download/download_stats.cc b/content/browser/download/download_stats.cc
index 1abbc8c48fdd9ace389cf5524dd28889c9c45165..1b729069fdf0c0f81a0c1d6c108643e985071162 100644
--- a/content/browser/download/download_stats.cc
+++ b/content/browser/download/download_stats.cc
@@ -173,4 +173,44 @@ void RecordDownloadMimeType(const std::string& mime_type_string) {
                             DOWNLOAD_CONTENT_MAX);
 }
 
+void RecordOpen(const base::Time& end, bool first) {
+  if (end.is_null())
+    return;
+  UMA_HISTOGRAM_LONG_TIMES("Download.OpenTime", (base::Time::Now() - end));
+  if (first) {
+    UMA_HISTOGRAM_LONG_TIMES("Download.FirstOpenTime",
+                             (base::Time::Now() - end));
+  }
+}
+
+void RecordHistorySize(int size) {
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.HistorySize",
+                              size,
+                              0/*min*/,
+                              kint32max/*max*/,
+                              (1 << 10)/*num_buckets*/);
+}
+
+void RecordHistorySize2(int size) {
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.HistorySize2",
+                              size,
+                              0/*min*/,
+                              kint32max/*max*/,
+                              (1 << 10)/*num_buckets*/);
+}
+
+void RecordShelfSize(int size) {
+  UMA_HISTOGRAM_ENUMERATION("Download.ShelfSize",
+                            size,
+                            128);
+}
+
+void RecordClearAllSize(int size) {
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.ClearAllSize",
+                              size,
+                              0/*min*/,
+                              kint32max/*max*/,
+                              (1 << 10)/*num_buckets*/);
+}
+
 }  // namespace download_stats