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

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 0770a14b29967b08247e43848b050041350a0898..daf48552f9a9927d1fca9d42fa97d4b4716e1529 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -419,6 +419,9 @@ const char kEnableDirectWrite[]             = "enable-direct-write";
 // Use high resolution timers for TimeTicks.
 const char kEnableHighResolutionTime[]      = "enable-high-resolution-time";
 
+// Device scale factor passed to certain processes like renderers, etc.
+const char kUseDeviceScaleFactor[]     = "use-device-scale-factor";
+
 // Enable the Win32K process mitigation policy for renderer processes which
 // prevents them from invoking user32 and gdi32 system calls which enter
 // the kernel. This is only supported on Windows 8 and beyond.