Move kInvalidDisplayID to display_constants.h.

ui/display/types/display_constants.h

 // Copyright 2014 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.
 
 #ifndef UI_DISPLAY_TYPES_DISPLAY_CONSTANTS_H_
 #define UI_DISPLAY_TYPES_DISPLAY_CONSTANTS_H_
 
+#include <stdint.h>
+
+namespace display {
+
+// Display ID that represents an invalid display. Often used as a default value
+// before display IDs are known.
+constexpr int64_t kInvalidDisplayId = -1;
+
+}  // namespace display
+
 namespace ui {
 
 // Used to describe the state of a multi-display configuration.
 enum MultipleDisplayState {
   MULTIPLE_DISPLAY_STATE_INVALID,
   MULTIPLE_DISPLAY_STATE_HEADLESS,
   MULTIPLE_DISPLAY_STATE_SINGLE,
   MULTIPLE_DISPLAY_STATE_DUAL_MIRROR,
   MULTIPLE_DISPLAY_STATE_DUAL_EXTENDED,
   // TODO(oshima): consolidate DUAL_EXTENDED and MULTI_EXTENDED.
@@ skipping 38 matching lines @@
   COLOR_PROFILE_STANDARD,
   COLOR_PROFILE_DYNAMIC,
   COLOR_PROFILE_MOVIE,
   COLOR_PROFILE_READING,
   NUM_COLOR_PROFILES,
 };
 
 }  // namespace ui
 
 #endif  // UI_DISPLAY_TYPES_DISPLAY_CONSTANTS_H_