resources: Prevent including the same resource in multiple pack files.

ash/test/ash_test_helper.cc

Index: ash/test/ash_test_helper.cc
diff --git a/ash/test/ash_test_helper.cc b/ash/test/ash_test_helper.cc
index 6cab8fd59455d9de7e7ecf65afea1db0d8feecd3..9995811054ed4d381b0bdd629f65d262f4d9c02e 100644
--- a/ash/test/ash_test_helper.cc
+++ b/ash/test/ash_test_helper.cc
@@ -126,7 +126,6 @@ void AshTestHelper::TearDown() {
     chromeos::DBusThreadManager::Shutdown();
     dbus_thread_manager_initialized_ = false;
   }
-  keyboard::ResetKeyboardForTesting();

[Nico, 2015/05/02 00:50:48]

?

[sadrul, 2015/05/02 04:17:09]

A new instance of ash::Shell gets created for each test, and it initializes the
virtual keyboard upon creation. The virtual keyboard installs the resource-pak
to the resource-bundle when it is initialized. However, the resource-bundle is
initialized only once for the entire test-suite. This trips the new check, since
the same resource-pak is attempted to load multiple times. So for the ash tests,
the keyboard is reset with the resource-bundle, so that the virtual keyboard
initialization does not attempt to load the resource-pak for each test.

[Nico, 2015/05/06 01:06:35]

I would've guessed that the intention of this is that the virtual keyboard is
dismissed after each test if it's open. With this change, it's only dismissed
once at the end of all tests.

Maybe it's good to land this separately and have someone familiar with the
virtual keyboard review it.

 #endif
 
   aura::Env::DeleteInstance();