base::EmplaceUnique

ui/views/controls/scroll_view_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/controls/scroll_view.h"
 
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "base/tuple.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/views/border.h"
 #include "ui/views/controls/scrollbar/base_scroll_bar_thumb.h"
 #include "ui/views/controls/scrollbar/native_scroll_bar.h"
 #include "ui/views/controls/scrollbar/native_scroll_bar_views.h"
 #include "ui/views/controls/scrollbar/overlay_scroll_bar.h"
 #include "ui/views/test/test_views.h"
 #include "ui/views/test/widget_test.h"
 
 #if defined(OS_MACOSX)
 #include "ui/base/test/scoped_preferred_scroller_style_mac.h"
 #endif
 
+namespace base {
+namespace internal {
+
+template <typename... Args>
+struct EmplaceUniqueResult {
+  using Tuple = std::tuple<Args...>;
+  Tuple params;
+
+  EmplaceUniqueResult(Args&&... args)
+      : params(std::forward<Args...>(args...)) {}
+
+  template <class T, std::size_t... I>
+  T* CreateNewT(IndexSequence<I...>) {
+    return new T(std::get<I>(params)...);
+  }
+
+  template <class T>
+  using UniquePtr = std::unique_ptr<T>;  // Avoids a presumbmit error.
+
+  template <class T>
+  operator UniquePtr<T>() {
+    return UniquePtr<T>(CreateNewT<T>(MakeIndexSequenceForTuple<Tuple>()));
+  }
+};
+
+}  // namespace internal
+
+template <typename... Args>
+typename internal::EmplaceUniqueResult<Args...> EmplaceUnique(Args&&... args) {
+  return internal::EmplaceUniqueResult<Args...>(std::forward<Args...>(args...));
+}
+
+}  // namespace base
+
 enum ScrollBarOrientation { HORIZONTAL, VERTICAL };
 
 namespace views {
 namespace test {
 
 class ScrollViewTestApi {
  public:
   explicit ScrollViewTestApi(ScrollView* scroll_view)
       : scroll_view_(scroll_view) {}
 
@@ skipping 110 matching lines @@
     scroll_view_.SetBoundsRect(default_outer_bounds);
     return contents;
   }
 
  protected:
 #if defined(OS_MACOSX)
   void SetOverlayScrollersEnabled(bool enabled) {
     // Ensure the old scroller override is destroyed before creating a new one.
     // Otherwise, the swizzlers are interleaved and restore incorrect methods.
     scroller_style_.reset();
-    scroller_style_ =
-        base::MakeUnique<ui::test::ScopedPreferredScrollerStyle>(enabled);
+    scroller_style_ = base::EmplaceUnique(enabled);
   }
 
  private:
   // Disable overlay scrollers by default. This needs to be set before
   // |scroll_view_| is initialized, otherwise scrollers will try to animate to
   // change modes, which requires a MessageLoop to exist. Tests should only
   // modify this via SetOverlayScrollersEnabled().
   std::unique_ptr<ui::test::ScopedPreferredScrollerStyle> scroller_style_ =
       base::MakeUnique<ui::test::ScopedPreferredScrollerStyle>(false);
 
@@ skipping 728 matching lines @@
   // Scroll via ScrollView API. Should be reflected on the impl side.
   offset.set_y(kDefaultHeight * 4);
   scroll_view->contents()->ScrollRectToVisible(offset);
   EXPECT_EQ(gfx::ScrollOffset(0, offset.y()), test_api.CurrentOffset());
 
   EXPECT_TRUE(compositor->GetScrollOffsetForLayer(layer_id, &impl_offset));
   EXPECT_EQ(gfx::ScrollOffset(0, offset.y()), impl_offset);
 }
 
 }  // namespace views