Use stricter type checking in UMA_HISTOGRAM_ENUMERATION

content/browser/download/download_stats.cc

 // Copyright (c) 2012 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/macros.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
@@ skipping 896 matching lines @@
 
 void RecordSavePackageEvent(SavePackageEvent event) {
   UMA_HISTOGRAM_ENUMERATION("Download.SavePackage",
                             event,
                             SAVE_PACKAGE_LAST_ENTRY);
 }
 
 void RecordOriginStateOnResumption(bool is_partial,
                                    int state) {
   if (is_partial)
-    UMA_HISTOGRAM_ENUMERATION("Download.OriginStateOnPartialResumption", state,
-                              ORIGIN_STATE_ON_RESUMPTION_MAX);
+    UMA_HISTOGRAM_EXACT_LINEAR(
+        "Download.OriginStateOnPartialResumption", state,
+        static_cast<int>(ORIGIN_STATE_ON_RESUMPTION_MAX));

[Alexei Svitkine (slow), 2017/05/31 20:22:24]

But these are actual enums, as defined in XML.

I don't think we should be changing to use EXACT_LINEAR macro when logically
these are enums. Can the types of the function params be updated instead?

[wychen, 2017/07/14 23:18:44]

Fixed. Some static casts are still needed because this enum is inherently a
bitmask.

   else
-    UMA_HISTOGRAM_ENUMERATION("Download.OriginStateOnFullResumption", state,
-                              ORIGIN_STATE_ON_RESUMPTION_MAX);
+    UMA_HISTOGRAM_EXACT_LINEAR(
+        "Download.OriginStateOnFullResumption", state,
+        static_cast<int>(ORIGIN_STATE_ON_RESUMPTION_MAX));
 }
 
 namespace {
 
 // Enumeration for histogramming purposes.
 // DO NOT CHANGE THE ORDERING OF THESE VALUES.
 enum DownloadConnectionSecurity {
   DOWNLOAD_SECURE,  // Final download url and its redirects all use https
   DOWNLOAD_TARGET_INSECURE,  // Final download url uses http, redirects are all
                              // https
@@ skipping 45 matching lines @@
 }
 
 void RecordDownloadHttpResponseCode(int response_code) {
   UMA_HISTOGRAM_CUSTOM_ENUMERATION(
       "Download.HttpResponseCode",
       net::HttpUtil::MapStatusCodeForHistogram(response_code),
       net::HttpUtil::GetStatusCodesForHistogram());
 }
 
 }  // namespace content