Add GetDisplayWithDisplayId to display::Screen.

chromecast/graphics/cast_screen.cc

Index: chromecast/graphics/cast_screen.cc
diff --git a/chromecast/graphics/cast_screen.cc b/chromecast/graphics/cast_screen.cc
index a31ebb208dca8ba4a2fe7b2da95cd25018121223..8316ad74ae611a85af5cc3768cfdacdb74abad0d 100644
--- a/chromecast/graphics/cast_screen.cc
+++ b/chromecast/graphics/cast_screen.cc
@@ -59,6 +59,15 @@ std::vector<display::Display> CastScreen::GetAllDisplays() const {
   return std::vector<display::Display>(1, display_);
 }
 
+bool CastScreen::GetDisplayWithDisplayId(int64_t display_id,
+                                         display::Display* display) const {
+  if (display_.id() == display_id) {
+    *display = display_;
+    return true;
+  }
+  return false;
+}
+
 display::Display CastScreen::GetDisplayNearestWindow(
     gfx::NativeWindow window) const {
   return display_;