mus/views: Fix creating gfx::Display in high-dpi.

ui/views/mus/screen_mus_unittest.cc

Index: ui/views/mus/screen_mus_unittest.cc
diff --git a/ui/views/mus/screen_mus_unittest.cc b/ui/views/mus/screen_mus_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fe80a72baa52da4eee32b9dd3c859d08f5faa3e8
--- /dev/null
+++ b/ui/views/mus/screen_mus_unittest.cc
@@ -0,0 +1,32 @@
+// Copyright 2016 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/mus/screen_mus.h"
+
+#include "base/command_line.h"
+#include "ui/gfx/screen.h"
+#include "ui/gfx/switches.h"
+#include "ui/views/mus/window_manager_connection.h"
+#include "ui/views/test/scoped_views_test_helper.h"
+#include "ui/views/test/views_test_base.h"
+
+namespace views {
+namespace {
+
+TEST(ScreenMusTest, ConsistentDisplayInHighDPI) {
+  base::MessageLoop message_loop(base::MessageLoop::TYPE_UI);
+  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
+      switches::kForceDeviceScaleFactor, "2");
+  ScopedViewsTestHelper test_helper;
+  gfx::Screen* screen = gfx::Screen::GetScreen();
+  std::vector<gfx::Display> displays = screen->GetAllDisplays();
+  ASSERT_FALSE(displays.empty());
+  for (const gfx::Display& display : displays) {
+    EXPECT_EQ(2.f, display.device_scale_factor());
+    EXPECT_EQ(display.work_area(), display.bounds());
+  }
+}
+
+}  // namespace
+}  // namespace views