[views-mus] Prevent creating a native OzonePlatform in mus tests.

ui/views/views_test_suite.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_VIEWS_TEST_SUITE_H_
 #define UI_VIEWS_VIEWS_TEST_SUITE_H_
 
 #include "base/test/test_suite.h"
 
 #if defined(USE_AURA)
@@ skipping 12 matching lines @@
   ~ViewsTestSuite() override;
 
   int RunTests();
   int RunTestsSerially();
 
  protected:
   // base::TestSuite:
   void Initialize() override;
   void Shutdown() override;
 
+#if defined(USE_AURA)
+  // Different test suites may wish to create Env differently.
+  virtual void InitializeEnv();
+  virtual void DestroyEnv();
+#endif
+
  private:
 #if defined(USE_AURA)
   std::unique_ptr<aura::Env> env_;
 #endif
   int argc_;
   char** argv_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewsTestSuite);
 };
 
 }  // namespace
 
 #endif  // UI_VIEWS_VIEWS_TEST_SUITE_H_