Record document mode histogram in UMA on every upload.

chrome/browser/metrics/signin_status_metrics_provider.h

Index: chrome/browser/metrics/signin_status_metrics_provider.h
diff --git a/chrome/browser/metrics/signin_status_metrics_provider.h b/chrome/browser/metrics/signin_status_metrics_provider.h
index 28c82077d60e80ac21da2cbfffa4cb3c6453012d..d8b3685840a239f4f6943a4496fa2398aad041c8 100644
--- a/chrome/browser/metrics/signin_status_metrics_provider.h
+++ b/chrome/browser/metrics/signin_status_metrics_provider.h
@@ -16,11 +16,16 @@
 #include "components/signin/core/browser/signin_manager_base.h"
 
 class Browser;
+class ChromeUserMetricsExtension;
 
 namespace base {
 class FilePath;
 }
 
+namespace metrics {
+class ChromeUserMetricsExtension;
+}
+
 // Collect login status of all opened profiles during one UMA session and record
 // the value into a histogram before UMA log is uploaded. It's currently not
 // supported on platform chromeos, Android or iOS.
@@ -31,10 +36,9 @@ class SigninStatusMetricsProvider : public metrics::MetricsProvider,
  public:
   virtual ~SigninStatusMetricsProvider();
 
-  // Record the collected sign-in status into a histogram and re-check current
-  // sign-in status to get prepared for the next UMA session. Called by
-  // MetricsServiceClient when it is collecting final metrics.
-  void RecordSigninStatusHistogram();
+  // metrics::MetricsProvider:
+  void ProvideGeneralMetrics(
+      metrics::ChromeUserMetricsExtension* uma_proto) override;
 
   // Factory method, creates a new instance of this class.
   static SigninStatusMetricsProvider* CreateInstance();