Revert of aura: Require explicit ownership of the Env instance.

ui/aura/test/aura_test_helper.cc

Index: ui/aura/test/aura_test_helper.cc
diff --git a/ui/aura/test/aura_test_helper.cc b/ui/aura/test/aura_test_helper.cc
index 230f215c513d7a84851855320d5013aa8fd66f4d..9d8c305201e7eb51ab72147183a06bb1f887ceb7 100644
--- a/ui/aura/test/aura_test_helper.cc
+++ b/ui/aura/test/aura_test_helper.cc
@@ -34,7 +34,8 @@
 
 AuraTestHelper::AuraTestHelper(base::MessageLoopForUI* message_loop)
     : setup_called_(false),
-      teardown_called_(false) {
+      teardown_called_(false),
+      env_created_(false) {
   DCHECK(message_loop);
   message_loop_ = message_loop;
   // Disable animations during tests.
@@ -56,8 +57,10 @@
 void AuraTestHelper::SetUp(ui::ContextFactory* context_factory) {
   setup_called_ = true;
 
-  if (!Env::GetInstanceDontCreate())
-    env_ = aura::Env::CreateInstance();
+  if (!Env::GetInstanceDontCreate()) {
+    env_created_ = true;
+    Env::CreateInstance(true);
+  }
   Env::GetInstance()->set_context_factory(context_factory);
   // Unit tests generally don't want to query the system, rather use the state
   // from RootWindow.
@@ -99,7 +102,8 @@
 
   ui::ShutdownInputMethodForTesting();
 
-  env_.reset();
+  if (env_created_)
+    Env::DeleteInstance();
 }
 
 void AuraTestHelper::RunAllPendingInMessageLoop() {