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

content/browser/download/download_stats.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/download/download_stats.h"
 
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 
 namespace download_stats {
@@ skipping 155 matching lines @@
       download_content = DOWNLOAD_CONTENT_VIDEO;
     }
   }
 
   // Record the value.
   UMA_HISTOGRAM_ENUMERATION("Download.ContentType",
                             download_content,
                             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*/,
+                              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 RecordShelfPendingSize(int size) {
+  UMA_HISTOGRAM_ENUMERATION("Download.ShelfPendingSize",
+                            size,
+                            128);
+}
+
+void RecordClearAllSize(int size) {
+  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.ClearAllSize",
+                              size,
+                              0/*min*/,
+                              kint32max/*max*/,
+                              (1 << 10)/*num_buckets*/);
+}
+
 }  // namespace download_stats