Moves FindDisplayIndexContainingPoint into display

ui/display/display_finder.h

Index: ui/display/display_finder.h
diff --git a/ui/display/display_finder.h b/ui/display/display_finder.h
index d63925923c77b719100caffa4917b16424065598..b66f044f5cc6a151b02fd482d10a9ef9418e2e21 100644
--- a/ui/display/display_finder.h
+++ b/ui/display/display_finder.h
@@ -17,7 +17,8 @@ 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);
@@ -28,6 +29,12 @@ DISPLAY_EXPORT const Display* FindDisplayWithBiggestIntersection(
     const std::vector<Display>& displays,
     const gfx::Rect& rect);
 
+// Returns the index in |displays| whose bounds contains |point_in_screen|.
+// Returns -1 if no such Display contains |point_in_screen|.
+DISPLAY_EXPORT int FindDisplayIndexContainingPoint(

[kylechar, 2017/03/06 18:00:20]

Would it be "more" correct to return an iterator into |displays| here? Not that
there would ever be more more than INT_MAX displays in reality .

[sky, 2017/03/06 18:22:00]

I just copy/pasted the code. But I agree, an iterator makes more sense here.
Updated.

+    const std::vector<Display>& displays,
+    const gfx::Point& point_in_screen);
+
 }  // namespace display
 
 #endif  // UI_DISPLAY_DISPLAY_FINDER_H_