Convert //extensions/browser from scoped_ptr to std::unique_ptr

extensions/browser/test_extension_registry_observer.cc

Index: extensions/browser/test_extension_registry_observer.cc
diff --git a/extensions/browser/test_extension_registry_observer.cc b/extensions/browser/test_extension_registry_observer.cc
index ab53b7a437ab7c96d891d70c4f078a0a9b630bed..ebdf1a85508249e855576839b372f313fad280e7 100644
--- a/extensions/browser/test_extension_registry_observer.cc
+++ b/extensions/browser/test_extension_registry_observer.cc
@@ -105,7 +105,7 @@ void TestExtensionRegistryObserver::OnExtensionUnloaded(
 }
 
 const Extension* TestExtensionRegistryObserver::Wait(
-    scoped_ptr<Waiter>* waiter) {
+    std::unique_ptr<Waiter>* waiter) {
   waiter->get()->Wait();
   const Extension* extension = waiter->get()->extension();
   // Reset the waiter for future uses.