Add histograms to the rendez-vous process (ProcessSingleton).

chrome/browser/process_singleton_win.cc

Index: chrome/browser/process_singleton_win.cc
diff --git a/chrome/browser/process_singleton_win.cc b/chrome/browser/process_singleton_win.cc
index 442458e086bc0edf3a04ac6040707f7486ff63be..c33fd1a511bb9effbd0a2c9d8546b644ca4f05d8 100644
--- a/chrome/browser/process_singleton_win.cc
+++ b/chrome/browser/process_singleton_win.cc
@@ -13,6 +13,7 @@
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/process/process.h"
 #include "base/process/process_info.h"
 #include "base/strings/string_number_conversions.h"
@@ -281,12 +282,22 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcess() {
 
 ProcessSingleton::NotifyResult
 ProcessSingleton::NotifyOtherProcessOrCreate() {
+  const base::TimeTicks begin_ticks = base::TimeTicks::Now();
   for (int i = 0; i < 2; ++i) {
     if (Create()) {
+      UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToCreate",
+                                 base::TimeTicks::Now() - begin_ticks);
       return PROCESS_NONE;  // This is the single browser process.
     }
     ProcessSingleton::NotifyResult result = NotifyOtherProcess();
     if (result == PROCESS_NOTIFIED || result == LOCK_ERROR) {
+      if (result == PROCESS_NOTIFIED) {
+        UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToNotify",
+                                   base::TimeTicks::Now() - begin_ticks);
+      } else {
+        UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToFailure",
+                                   base::TimeTicks::Now() - begin_ticks);
+      }
       // The single browser process was notified, the user chose not to
       // terminate a hung browser, or the lock file could not be created.
       // Nothing more to do.
@@ -297,6 +308,8 @@ ProcessSingleton::NotifyOtherProcessOrCreate() {
     // terminated. Retry once if this is the first time; otherwise, fall through
     // to report that the process must exit because the profile is in use.
   }
+  UMA_HISTOGRAM_MEDIUM_TIMES("Chrome.ProcessSingleton.TimeToFailure",
+                             base::TimeTicks::Now() - begin_ticks);
   return PROFILE_IN_USE;
 }