Wait visibility changes with RunLoop.

chrome/browser/metrics/desktop_session_duration/chrome_visibility_observer.h

Index: chrome/browser/metrics/desktop_session_duration/chrome_visibility_observer.h
diff --git a/chrome/browser/metrics/desktop_session_duration/chrome_visibility_observer.h b/chrome/browser/metrics/desktop_session_duration/chrome_visibility_observer.h
index 7740391d4d43da57a1ec31ae0f1b8b4d38c177ab..3122503228513733ac01f1607dc47232b132e0ba 100644
--- a/chrome/browser/metrics/desktop_session_duration/chrome_visibility_observer.h
+++ b/chrome/browser/metrics/desktop_session_duration/chrome_visibility_observer.h
@@ -21,6 +21,10 @@ class ChromeVisibilityObserver : public chrome::BrowserListObserver {
   // by tests.
   virtual void SendVisibilityChangeEvent(bool active, base::TimeDelta time_ago);
 
+  // chrome::BrowserListObserver:
+  // In protected section for test.
+  void OnBrowserRemoved(Browser* browser) override;
+
  private:
   // Cancels visibility change in case when the browser becomes visible after a
   // short gap.
@@ -29,7 +33,6 @@ class ChromeVisibilityObserver : public chrome::BrowserListObserver {
   // chrome::BrowserListObserver:
   void OnBrowserSetLastActive(Browser* browser) override;
   void OnBrowserNoLongerActive(Browser* browser) override;
-  void OnBrowserRemoved(Browser* browser) override;
 
   // Sets |visibility_gap_timeout_| based on variation params.
   void InitVisibilityGapTimeout();