Pass the device scale factor in the command line to renderer processes.

ui/base/win/dpi_setup.cc

Index: ui/base/win/dpi_setup.cc
diff --git a/ui/base/win/dpi_setup.cc b/ui/base/win/dpi_setup.cc
index 423b788132ac0a3cd5153fd6625d4e6b3b0d20f7..ee456c6ad35167b69ef701a70ff5eade6c42e4a7 100644
--- a/ui/base/win/dpi_setup.cc
+++ b/ui/base/win/dpi_setup.cc
@@ -13,7 +13,10 @@ namespace ui {
 namespace win {
 
 void InitDeviceScaleFactor() {
-  gfx::InitDeviceScaleFactor(gfx::GetDPIScale());
+  // Don't initialize the device scale factor if it has already been
+  // initialized.
+  if (!gfx::win::GetDeviceScaleFactor())
+    gfx::InitDeviceScaleFactor(gfx::GetDPIScale());
 }
 
 }  // namespace win