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..3f73b45eb4a2f6721e20dd33bd97a334eec09bd9 100644
--- a/content/browser/download/download_stats.cc
+++ b/content/browser/download/download_stats.cc
@@ -173,4 +173,56 @@ void RecordDownloadMimeType(const std::string& mime_type_string) {
                             DOWNLOAD_CONTENT_MAX);
 }
 
+void RecordOpen(const base::Time& end, bool first) {
+  if (!end.is_null()) {
+    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*/,
+                              (1 << 10)/*max*/,
+                              32/*num_buckets*/);
+}
+
+void RecordShelfClose(int size, int pending, bool autoclose) {
+  if (autoclose) {
+    UMA_HISTOGRAM_ENUMERATION("Download.ShelfSizeOnAutoClose",
+                              size,
+                              128);
+    UMA_HISTOGRAM_ENUMERATION("Download.ShelfPendingSizeOnAutoClose",
+                              pending,
+                              128);
+  } else {
+    UMA_HISTOGRAM_ENUMERATION("Download.ShelfSizeOnUserClose",
+                              size,
+                              128);
+    UMA_HISTOGRAM_ENUMERATION("Download.ShelfPendingSizeOnUserClose",
+                              pending,
+                              128);
+  }
+}
+
+void RecordClearAllSize(int size) {
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.ClearAllSize",
+                              size,
+                              0/*min*/,
+                              (1 << 10)/*max*/,
+                              32/*num_buckets*/);
+}
+
+void RecordOpensOutstanding(int size) {
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.OpensOutstanding",
+                              size,
+                              0/*min*/,
+                              (1 << 10)/*max*/,
+                              32/*num_buckets*/);
+}
+
 }  // namespace download_stats