Add display::GetDisplayNearestView

ui/display/screen.h

Index: ui/display/screen.h
diff --git a/ui/display/screen.h b/ui/display/screen.h
index 3bff5bdb6406f2bb5256fb552cb8642c5951b2dd..8ea02453b3735185581bd69d3797a7ae64f2ce88 100644
--- a/ui/display/screen.h
+++ b/ui/display/screen.h
@@ -58,8 +58,14 @@ class DISPLAY_EXPORT Screen {
   // Returns the display nearest the specified window.
   // If the window is NULL or the window is not rooted to a display this will
   // return the primary display.
+  // TODO(jinsukkim): Fix the parameter type to |gfx::NativeWindow|.

[tapted, 2017/03/06 00:01:49]

I think the CL is simple enough that we should pursue this now. And we need to
force a bit more "fallout" before we know if this approach is going to work - as
it is, nothing is calling WindowForView(). So it is dead code, and we try not to
add dead code to Chrome unless we are sure it will be used.

[Jinsuk Kim, 2017/03/06 06:06:19]

No problem. Will add it when it gets actually put to use. Removed.

   virtual Display GetDisplayNearestWindow(gfx::NativeView view) const = 0;
 
+  // Returns the display nearest the specified view. It may still use the window
+  // that contains the view (i.e. if a window is spread over two displays,
+  // the location of the view within that window won't influence the result).
+  virtual Display GetDisplayNearestView(gfx::NativeView view) const;
+
   // Returns the display nearest the specified point. |point| should be in DIPs.
   virtual Display GetDisplayNearestPoint(const gfx::Point& point) const = 0;
 
@@ -91,6 +97,8 @@ class DISPLAY_EXPORT Screen {
   bool GetDisplayWithDisplayId(int64_t display_id, Display* display) const;
 
  private:
+  static gfx::NativeWindow WindowForView(gfx::NativeView view);
+
   DISALLOW_COPY_AND_ASSIGN(Screen);
 };