Moves FindDisplayIndexContainingPoint into display

ui/display/display_finder.h

 // Copyright 2016 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_DISPLAY_FINDER_H_
 #define UI_DISPLAY_DISPLAY_FINDER_H_
 
 #include <vector>
 
 #include "ui/display/display_export.h"
 
 namespace gfx {
 class Point;
 class Rect;
 }
 
 namespace display {
 class Display;
 
-// Returns the display in |displays| closest to |point|.
+// Returns the display containing |point|. If no displays contain |point|, then
+// this returns the display closest to |point|.
 DISPLAY_EXPORT const Display* FindDisplayNearestPoint(
     const std::vector<Display>& displays,
     const gfx::Point& point);
 
 // Returns the display in |displays| with the biggest intersection of |rect|.
 // If none of the displays intersect |rect| null is returned.
 DISPLAY_EXPORT const Display* FindDisplayWithBiggestIntersection(
     const std::vector<Display>& displays,
     const gfx::Rect& rect);
 
+// Returns an iterator into |displays| of the Display whose bounds contains
+// |point_in_screen|, or displays.end() if no Displays contains
+// |point_in_screen|.
+DISPLAY_EXPORT std::vector<Display>::const_iterator FindDisplayContainingPoint(
+    const std::vector<Display>& displays,
+    const gfx::Point& point_in_screen);
+
 }  // namespace display
 
 #endif  // UI_DISPLAY_DISPLAY_FINDER_H_