Add FakeDisplayDelegate for off device usage.

ui/display/types/native_display_delegate.h

Index: ui/display/types/native_display_delegate.h
diff --git a/ui/display/types/native_display_delegate.h b/ui/display/types/native_display_delegate.h
index b17be8f1cffda92a19ad1e77a6591bd75486a8dc..0ebb6ef0c818b72852caf45c973a44803adabd6d 100644
--- a/ui/display/types/native_display_delegate.h
+++ b/ui/display/types/native_display_delegate.h
@@ -12,6 +12,7 @@
 #include "base/callback.h"
 #include "ui/display/types/display_constants.h"
 #include "ui/display/types/display_types_export.h"
+#include "ui/display/types/fake_display_controller.h"
 
 namespace gfx {
 class Point;
@@ -21,7 +22,6 @@ class Size;
 namespace ui {
 class DisplayMode;
 class DisplaySnapshot;
-
 class NativeDisplayObserver;
 
 struct GammaRampRGBEntry;
@@ -117,6 +117,11 @@ class DISPLAY_TYPES_EXPORT NativeDisplayDelegate {
   virtual void AddObserver(NativeDisplayObserver* observer) = 0;
 
   virtual void RemoveObserver(NativeDisplayObserver* observer) = 0;
+
+  // Returns a fake display controller that can modify the fake display state.
+  // Will return null if not needed, most likely because the delegate is
+  // intended for use on device and doesn't need to fake the display state.
+  virtual display::FakeDisplayController* GetFakeDisplayController() = 0;
 };
 
 }  // namespace ui