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

content/public/common/content_switches.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/public/common/content_switches.h"
 
 #include "base/command_line.h"
 
 namespace switches {
 
@@ skipping 401 matching lines @@
 #if defined(OS_WIN)
 // Disable the Legacy Window which corresponds to the size of the WebContents.
 const char kDisableLegacyIntermediateWindow[] = "disable-legacy-window";
 
 // Enables the DirectWrite font rendering system on windows.
 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.
 const char kEnableWin32kRendererLockDown[]
     = "enable_win32k_renderer_lockdown";
 #endif
 
 // Paint content on the compositor thread instead of the main thread.
 const char kEnableImplSidePainting[]        = "enable-impl-side-painting";
 
@@ skipping 546 matching lines @@
 
 // Disables support for Core Animation plugins. This is triggered when
 // accelerated compositing is disabled. See http://crbug.com/122430 .
 const char kDisableCoreAnimationPlugins[] =
     "disable-core-animation-plugins";
 #endif
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches