Debug the generic session restore failure.

chrome/browser/sessions/session_service_unittest.cc

Index: chrome/browser/sessions/session_service_unittest.cc
diff --git a/chrome/browser/sessions/session_service_unittest.cc b/chrome/browser/sessions/session_service_unittest.cc
index 748ee7a14cd54810657a64b7e76f75b4d53f51db..802cbae31212e209941c7ade2f03b1434725830e 100644
--- a/chrome/browser/sessions/session_service_unittest.cc
+++ b/chrome/browser/sessions/session_service_unittest.cc
@@ -8,6 +8,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/path_service.h"
+#include "base/run_loop.h"
 #include "base/scoped_temp_dir.h"
 #include "base/stl_util.h"
 #include "base/string_number_conversions.h"
@@ -96,6 +97,11 @@ class SessionServiceTest : public BrowserWithTestWindowTest,
     // Forces closing the file.
     helper_.set_service(NULL);
 
+    // SessionBackend posts delayed tasks and might stay alive a bit longer than
+    // SessionService. Make sure the tasks run and the backend is destroyed.
+    base::RunLoop loop;
+    loop.RunUntilIdle();
+
     SessionService* session_service = new SessionService(path_);
     helper_.set_service(session_service);
     helper_.ReadWindows(windows);