Add context to gfx::Screen calls in support of simultaneous desktop+ash

content/shell/shell_aura.cc

Index: content/shell/shell_aura.cc
diff --git a/content/shell/shell_aura.cc b/content/shell/shell_aura.cc
index ebbd75eaf30b1c217cbf339e525d16b94bee4e00..7e1a1e893b43a50c91ac9c78a2cea01973e3eb61 100644
--- a/content/shell/shell_aura.cc
+++ b/content/shell/shell_aura.cc
@@ -289,7 +289,8 @@ void Shell::PlatformInitialize() {
 #endif
   aura::Env::GetInstance()->SetDisplayManager(new aura::SingleDisplayManager);
   stacking_client_ = new aura::DesktopStackingClient();
-  gfx::Screen::SetInstance(aura::CreateDesktopScreen());
+  gfx::Screen::SetScreenInstance(
+      gfx::SCREEN_TYPE_NATIVE, aura::CreateDesktopScreen());
   views_delegate_ = new ShellViewsDelegateAura();
 
   CommandLine::ForCurrentProcess()->AppendSwitch(views::switches::kDesktopAura);