Convert //ash from scoped_ptr to std::unique_ptr

ash/shelf/shelf_model_unittest.cc

Index: ash/shelf/shelf_model_unittest.cc
diff --git a/ash/shelf/shelf_model_unittest.cc b/ash/shelf/shelf_model_unittest.cc
index 05fea6d3fbfc9c3fcd434834cdeffb933d78f65e..170fac6b92c9c12feb260ff7fb823a6ba467d79f 100644
--- a/ash/shelf/shelf_model_unittest.cc
+++ b/ash/shelf/shelf_model_unittest.cc
@@ -91,8 +91,8 @@ class ShelfModelTest : public testing::Test {
     model_.reset();
   }
 
-  scoped_ptr<ShelfModel> model_;
-  scoped_ptr<TestShelfModelObserver> observer_;
+  std::unique_ptr<ShelfModel> model_;
+  std::unique_ptr<TestShelfModelObserver> observer_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ShelfModelTest);