Move kInvalidDisplayID to display_constants.h.

ui/display/display.h

Index: ui/display/display.h
diff --git a/ui/display/display.h b/ui/display/display.h
index 24949393e243ac28da6d7f4e201f53eafa19e8b6..199f51268bb2121aa42c490650254797521cf68d 100644
--- a/ui/display/display.h
+++ b/ui/display/display.h
@@ -9,6 +9,7 @@
 
 #include "base/compiler_specific.h"
 #include "ui/display/display_export.h"
+#include "ui/display/types/display_constants.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/icc_profile.h"
 
@@ -65,7 +66,8 @@ class DISPLAY_EXPORT Display final {
     TOUCH_SUPPORT_UNAVAILABLE,
   };
 
-  enum : int64_t { kInvalidDisplayID = -1 };
+  // Use display::kInvalidDisplayID from display_constants.h in new code.
+  enum : int64_t { kInvalidDisplayID = display::kInvalidDisplayID };

[sadrul, 2016/11/21 17:31:17]

Get rid of it?

[kylechar, 2016/11/21 17:51:18]

It's still used everywhere that isn't src/ui/* but I'll switch that next and
remove it. Added a TODO.

 
   // Creates a display with kInvalidDisplayID as default.
   Display();