views/mus: Have explicit ownership of views::WindowManagerConnection.

ui/views/mus/views_mus_test_suite.cc

Index: ui/views/mus/views_mus_test_suite.cc
diff --git a/ui/views/mus/views_mus_test_suite.cc b/ui/views/mus/views_mus_test_suite.cc
index aac10d9ea9d869fd436de00803d6c3d10392b4b7..142362b1d75edfaaf9fb22d77455f1234a44c5b5 100644
--- a/ui/views/mus/views_mus_test_suite.cc
+++ b/ui/views/mus/views_mus_test_suite.cc
@@ -46,11 +46,13 @@ class PlatformTestHelperMus : public PlatformTestHelper {
                         const shell::Identity& identity) {
     // It is necessary to recreate the WindowManagerConnection for each test,
     // since a new MessageLoop is created for each test.
-    WindowManagerConnection::Create(connector, identity);
+    connection_ = WindowManagerConnection::Create(connector, identity);
   }
-  ~PlatformTestHelperMus() override { WindowManagerConnection::Reset(); }
+  ~PlatformTestHelperMus() override {}
 
  private:
+  std::unique_ptr<WindowManagerConnection> connection_;
+
   DISALLOW_COPY_AND_ASSIGN(PlatformTestHelperMus);
 };
 
@@ -85,8 +87,6 @@ class ShellConnection {
   }
 
   ~ShellConnection() {
-    if (views::WindowManagerConnection::Exists())
-      views::WindowManagerConnection::Reset();
     base::WaitableEvent wait(base::WaitableEvent::ResetPolicy::AUTOMATIC,
                              base::WaitableEvent::InitialState::NOT_SIGNALED);
     thread_.task_runner()->PostTask(