Force 2.25dsf default scale factor to deal with the panel issue.

See bug for details.

Bug: b/74845106
Test: manual.
Change-Id: I079ab633524e8cbee7ff19abe1202a43b8b7edfe
Reviewed-on: https://chromium-review.googlesource.com/1156864Reviewed-by: Malay Keshav <malaykeshav@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579803}

ui/display/manager/display_change_observer.cc

@@ -272,9 +272,14 @@ ManagedDisplayInfo DisplayChangeObserver::CreateManagedDisplayInfo(
                   ? 0
                   : kInchInMm * mode_info->size().width() /
                         snapshot->physical_size().width();
+  constexpr gfx::Size k225DisplaySizeHack(3000, 2000);
 
   if (snapshot->type() == DISPLAY_CONNECTION_TYPE_INTERNAL) {
-    if (dpi)
+    // TODO(oshima): This is a stopgap hack to deal with b/74845106.
+    // Remove this hack when it's resolved.
+    if (mode_info->size() == k225DisplaySizeHack)
+      device_scale_factor = 2.25f;
+    else if (dpi)
       device_scale_factor = FindDeviceScaleFactor(dpi);
   } else {
     ManagedDisplayMode mode;