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

chromecast/browser/cast_browser_main_parts.cc

Index: chromecast/browser/cast_browser_main_parts.cc
diff --git a/chromecast/browser/cast_browser_main_parts.cc b/chromecast/browser/cast_browser_main_parts.cc
index bf409cdcc7299743530227c815fb0bdb0c4545e6..cfffa672ffffc694d4593d6f49a7a68758c900ce 100644
--- a/chromecast/browser/cast_browser_main_parts.cc
+++ b/chromecast/browser/cast_browser_main_parts.cc
@@ -60,6 +60,7 @@
 
 #if defined(USE_AURA)
 #include "chromecast/graphics/cast_screen.h"
+#include "ui/aura/env.h"
 #include "ui/gfx/screen.h"
 #endif
 
@@ -389,6 +390,10 @@
   cast_browser_process_->metrics_service_client()->Finalize();
   cast_browser_process_.reset();
 
+#if defined(USE_AURA)
+  aura::Env::DeleteInstance();
+#endif
+
   DeregisterKillOnAlarm();
 #endif