Record shutdown type UMA

chrome/browser/browser_shutdown.cc

Index: chrome/browser/browser_shutdown.cc
diff --git a/chrome/browser/browser_shutdown.cc b/chrome/browser/browser_shutdown.cc
index 4af6c31b616b2c4205cb17d72e21bb679a6d0baf..555a9ceb2bffe07476cc0d47f66aa9e02511f8ff 100644
--- a/chrome/browser/browser_shutdown.cc
+++ b/chrome/browser/browser_shutdown.cc
@@ -83,6 +83,7 @@ const char kShutdownMsFile[] = "chrome_shutdown_ms.txt";
 const char* ToShutdownTypeString(ShutdownType type) {
   switch (type) {
     case NOT_VALID:
+    case SHUTDOWN_TYPE_MAX_VALUE:
       NOTREACHED();
       return "";
     case WINDOW_CLOSE:
@@ -327,6 +328,9 @@ void ReadLastShutdownInfo() {
   prefs->SetInteger(prefs::kShutdownNumProcesses, 0);
   prefs->SetInteger(prefs::kShutdownNumProcessesSlow, 0);
 
+  UMA_HISTOGRAM_ENUMERATION("Shutdown.ShutdownType", type,
+                            SHUTDOWN_TYPE_MAX_VALUE);
+
   // Read and delete the file on the file thread.
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,