Modifies the threshold for hidpi displays.

ui/display/display_util.h

Index: ui/display/display_util.h
diff --git a/ui/display/display_util.h b/ui/display/display_util.h
index f8c0bd241074b21ad3662810e0f5d6d8fd808b26..0928ef5c84648914a51151f617f2c815399f8639 100644
--- a/ui/display/display_util.h
+++ b/ui/display/display_util.h
@@ -14,6 +14,12 @@ namespace ui {
 // be ignored.
 DISPLAY_EXPORT bool IsDisplaySizeBlackListed(const gfx::Size& physical_size);
 
+// Returns the desired device scale factor for the display with the given
+// physical_size and resoultion.
+DISPLAY_EXPORT float GetScaleFactor(
+    const gfx::Size& physical_size_in_mm,
+    const gfx::Size& screen_size_in_pixels);
+
 }  // namespace ui
 
 #endif  // UI_DISPLAY_DISPLAY_UTIL_H_