Modifies the threshold for hidpi displays.

ash/display/display_change_observer_chromeos_unittest.cc

Index: ash/display/display_change_observer_chromeos_unittest.cc
diff --git a/ash/display/display_change_observer_chromeos_unittest.cc b/ash/display/display_change_observer_chromeos_unittest.cc
index 118e82653ee3d327c16e63706f42d7c96e7f7d1a..0c58b7002ff5e6111afcb2aa5445e7ec742ae60b 100644
--- a/ash/display/display_change_observer_chromeos_unittest.cc
+++ b/ash/display/display_change_observer_chromeos_unittest.cc
@@ -82,4 +82,30 @@ TEST_F(DisplayChangeObserverTest, GetDisplayModeList) {
   EXPECT_EQ(0u, display_modes.size());
 }
 
+TEST_F(DisplayChangeObserverTest, GetScaleFactor) {
+  // Normal chromebook spec. DPI ~= 130
+  EXPECT_EQ(1.0f, DisplayChangeObserver::GetScaleFactor(
+      gfx::Size(256, 144), gfx::Size(1366, 768)));
+
+  // HiDPI like Pixel. DPI ~= 240
+  EXPECT_EQ(2.0f, DisplayChangeObserver::GetScaleFactor(
+      gfx::Size(272, 181), gfx::Size(2560, 1700)));
+
+  // A large external display but normal pixel density. DPI ~= 100
+  EXPECT_EQ(1.0f, DisplayChangeObserver::GetScaleFactor(
+      gfx::Size(641, 400), gfx::Size(2560, 1600)));
+
+  // A large external display with high pixel density. DPI ~= 157
+  EXPECT_EQ(2.0f, DisplayChangeObserver::GetScaleFactor(
+      gfx::Size(621, 341), gfx::Size(3840, 2160)));
+
+  // 4K resolution but the display is physically even larger. DPI ~= 114
+  EXPECT_EQ(1.0f, DisplayChangeObserver::GetScaleFactor(
+      gfx::Size(854, 481), gfx::Size(3840, 2160)));
+
+  // Corner case; slightly higher density but smaller screens. DPI ~= 165
+  EXPECT_EQ(1.0f, DisplayChangeObserver::GetScaleFactor(
+      gfx::Size(293, 165), gfx::Size(1920, 1080)));
+}
+
 }  // namespace ash