Modifies the threshold for hidpi displays.

ui/display/display_util_unittest.cc

Index: ui/display/display_util_unittest.cc
diff --git a/ui/display/display_util_unittest.cc b/ui/display/display_util_unittest.cc
index 8a63ef292744feacf4305c46a7db2406907a3abf..8b426734c1ee5d4c38ecbda2f4d7daeb4c6e6936 100644
--- a/ui/display/display_util_unittest.cc
+++ b/ui/display/display_util_unittest.cc
@@ -20,4 +20,34 @@ TEST(DisplayUtilTest, TestBlackListedDisplay) {
   EXPECT_FALSE(IsDisplaySizeBlackListed(gfx::Size(272, 181)));
 }
 
+TEST(DisplayUtilTest, GetScaleFactor) {
+  // Normal chromebook spec. DPI ~= 130
+  EXPECT_EQ(1.0f, GetScaleFactor(
+      gfx::Size(256, 144), gfx::Size(1366, 768)));
+
+  // HiDPI like Pixel. DPI ~= 240
+  EXPECT_EQ(2.0f, GetScaleFactor(
+      gfx::Size(272, 181), gfx::Size(2560, 1700)));
+
+  // A large external display but normal pixel density. DPI ~= 100
+  EXPECT_EQ(1.0f, GetScaleFactor(
+      gfx::Size(641, 400), gfx::Size(2560, 1600)));
+
+  // A large external display with high pixel density. DPI ~= 157
+  EXPECT_EQ(2.0f, GetScaleFactor(
+      gfx::Size(621, 341), gfx::Size(3840, 2160)));
+
+  // 4K resolution but the display is physically even larger. DPI ~= 114
+  EXPECT_EQ(1.0f, GetScaleFactor(
+      gfx::Size(854, 481), gfx::Size(3840, 2160)));
+
+  // 21.5 inch, 1080p. DPI ~= 102
+  EXPECT_EQ(1.0f, GetScaleFactor(
+      gfx::Size(476, 267), gfx::Size(1920, 1080)));
+
+  // Corner case; slightly higher density but smaller screens. DPI ~= 165
+  EXPECT_EQ(1.0f, GetScaleFactor(
+      gfx::Size(293, 165), gfx::Size(1920, 1080)));
+}
+
 }  // namespace ui