Add GetDisplayWithDisplayId to display::Screen.

blimp/engine/app/ui/blimp_screen.cc

Index: blimp/engine/app/ui/blimp_screen.cc
diff --git a/blimp/engine/app/ui/blimp_screen.cc b/blimp/engine/app/ui/blimp_screen.cc
index c10396af01298a574225b75bc9a1aa82ee9f769d..e195f2eaa72e66ea09183286441ab94750cebf78 100644
--- a/blimp/engine/app/ui/blimp_screen.cc
+++ b/blimp/engine/app/ui/blimp_screen.cc
@@ -66,6 +66,15 @@ std::vector<display::Display> BlimpScreen::GetAllDisplays() const {
   return std::vector<display::Display>(1, display_);
 }
 
+bool BlimpScreen::GetDisplayWithDisplayId(int64_t display_id,
+                                          display::Display* display) const {
+  if (display_.id() == display_id) {
+    *display = display_;
+    return true;
+  }
+  return false;
+}
+
 display::Display BlimpScreen::GetDisplayNearestWindow(
     gfx::NativeWindow window) const {
   return display_;