Use 1.25 DSF for 150~180 DPI

ash/display/display_change_observer_chromeos_unittest.cc

 // Copyright 2013 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 "ash/display/display_change_observer_chromeos.h"
 
 #include "ash/display/display_info.h"
 #include "base/memory/scoped_vector.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/display/chromeos/display_configurator.h"
@@ skipping 64 matching lines @@
   EXPECT_EQ(display_modes[5].refresh_rate, 60);
 
   // Outputs without any modes shouldn't cause a crash.
   modes.clear();
   display_snapshot.set_modes(modes.get());
 
   display_modes = DisplayChangeObserver::GetDisplayModeList(output);
   EXPECT_EQ(0u, display_modes.size());
 }
 
+TEST_F(DisplayChangeObserverTest, FindDeviceScaleFactor) {
+  // 19.5" 1600x900
+  EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(94.14f));
+
+  // 21.5" 1920x1080
+  EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(102.46f));
+
+  // 12.1" 1280x800
+  EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(124.75f));
+
+  // 13.3" 1920x1080
+  EXPECT_EQ(1.25f, DisplayChangeObserver::FindDeviceScaleFactor(157.35f));
+
+  // 14" 1920x1080
+  EXPECT_EQ(1.25f, DisplayChangeObserver::FindDeviceScaleFactor(165.63f));
+
+  // 12.85" 2560x1700
+  EXPECT_EQ(2.0f, DisplayChangeObserver::FindDeviceScaleFactor(239.15f));
+
+  // Erroneous values should still work.
+  EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(-100.0f));
+  EXPECT_EQ(1.0f, DisplayChangeObserver::FindDeviceScaleFactor(0.0f));
+  EXPECT_EQ(2.0f, DisplayChangeObserver::FindDeviceScaleFactor(10000.0f));
+}
+
 }  // namespace ash