aura: Require explicit ownership of the Env instance.

ash/test/ash_interactive_ui_test_base.h

Index: ash/test/ash_interactive_ui_test_base.h
diff --git a/ash/test/ash_interactive_ui_test_base.h b/ash/test/ash_interactive_ui_test_base.h
index b6526b4ffd3c0ead31457e7fd17f7c0248adf390..0fb8cf8c20a24ff4a7ec1bd5a37673cc38906fab 100644
--- a/ash/test/ash_interactive_ui_test_base.h
+++ b/ash/test/ash_interactive_ui_test_base.h
@@ -5,11 +5,16 @@
 #ifndef ASH_TEST_ASH_INTERACTIVE_UI_TEST_BASE_H_
 #define ASH_TEST_ASH_INTERACTIVE_UI_TEST_BASE_H_
 
+#include <memory>
 #include <string>
 
 #include "ash/test/ash_test_base.h"
 #include "base/macros.h"
 
+namespace aura {
+class Env;
+}
+
 namespace ash {
 namespace test {
 
@@ -24,6 +29,7 @@ class AshInteractiveUITestBase : public AshTestBase {
   void TearDown() override;
 
  private:
+  std::unique_ptr<aura::Env> env_;
   DISALLOW_COPY_AND_ASSIGN(AshInteractiveUITestBase);
 };