Implement Sebastien's overlay scrollbars for native UI (Views).

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 "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/overlay_scroll_bar.h"
 #include "ui/views/controls/scrollbar/scroll_bar_views.h"
 #include "ui/views/test/test_views.h"
+#include "ui/views/test/views_test_base.h"
 #include "ui/views/test/widget_test.h"
 
 #if defined(OS_MACOSX)
 #include "ui/base/test/scoped_preferred_scroller_style_mac.h"
 #endif
 
 enum ScrollBarOrientation { HORIZONTAL, VERTICAL };
 
 namespace views {
 namespace test {
@@ skipping 94 matching lines @@
 ui::MouseEvent TestLeftMouseAt(const gfx::Point& location, ui::EventType type) {
   return ui::MouseEvent(type, location, location, base::TimeTicks(),
                         ui::EF_LEFT_MOUSE_BUTTON, ui::EF_LEFT_MOUSE_BUTTON);
 }
 
 }  // namespace
 
 using test::ScrollViewTestApi;
 
 // Simple test harness for testing a ScrollView directly.
-class ScrollViewTest : public testing::Test {
+class ScrollViewTest : public ViewsTestBase {
  public:
   ScrollViewTest() {}
 
   View* InstallContents() {
     const gfx::Rect default_outer_bounds(0, 0, 100, 100);
     View* contents = new View;
     scroll_view_.SetContents(contents);
     scroll_view_.SetBoundsRect(default_outer_bounds);
     return contents;
   }
@@ skipping 746 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