Add ScopedStubEnterpriseInstallAttributes for tests to set test install attributes.

chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h

Index: chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h
diff --git a/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h b/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h
index 83ab02c0c7ed79e2e0de0d261a3558db736f3a0f..86b34aa0dd501d0fa83afb5fc608935bfc32b487 100644
--- a/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h
+++ b/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h
@@ -92,9 +92,11 @@ class BrowserPolicyConnectorChromeOS : public ChromeBrowserPolicyConnector {
   }
 
   // Sets the install attributes for testing. Must be called before the browser
-  // is created. Takes ownership of |attributes|.
+  // is created. RemoveInstallAttributesForTesting must be called after the test
+  // to free the attributes.
   static void SetInstallAttributesForTesting(
       EnterpriseInstallAttributes* attributes);
+  static void RemoveInstallAttributesForTesting();
 
   // Registers device refresh rate pref.
   static void RegisterPrefs(PrefRegistrySimple* registry);