about_flags::ReportCustomFlags() should use signed 32-bit IDs.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index dd246e7703009eaed6fac106b2a59b162cbd0b7c..da7f181dec00aaaa16bc261da142248190b99c8c 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -65,7 +65,7 @@ using base::UserMetricsAction;
 
 namespace about_flags {
 
-const uint32_t kBadSwitchFormatHistogramId = 0;
+const int32_t kBadSwitchFormatHistogramId = 0;
 
 // Macros to simplify specifying the type.
 #define SINGLE_VALUE_TYPE_AND_VALUE(command_line_switch, switch_value) \
@@ -2238,8 +2238,8 @@ void RecordUMAStatistics(FlagsStorage* flags_storage) {
   content::RecordAction(UserMetricsAction("StartupTick"));
 }
 
-uint32_t GetSwitchUMAId(const std::string& switch_name) {
-  return static_cast<uint32_t>(metrics::HashMetricName(switch_name));
+int32_t GetSwitchUMAId(const std::string& switch_name) {

[sky, 2014/08/28 23:27:29]

Shouldn't you use the same types as used by histogram, by which I mean a common
typedef?

[Alexander Alekseev, 2014/08/30 04:41:14]

Done.

+  return static_cast<int32_t>(metrics::HashMetricName(switch_name));
 }
 
 void ReportCustomFlags(const std::string& uma_histogram_hame,