gfx::Screen: Replace GetWindowUnderCursor() with IsWindowUnderCursor().

ui/gfx/test/test_screen.cc

Index: ui/gfx/test/test_screen.cc
diff --git a/ui/gfx/test/test_screen.cc b/ui/gfx/test/test_screen.cc
index 31361dd0151dfbd133b7b2ceee46172c1889cbc6..d0729c1877bac3af96fad63523d9e11df2327f58 100644
--- a/ui/gfx/test/test_screen.cc
+++ b/ui/gfx/test/test_screen.cc
@@ -19,8 +19,8 @@ gfx::Point TestScreen::GetCursorScreenPoint() {
   return gfx::Point();
 }
 
-gfx::NativeWindow TestScreen::GetWindowUnderCursor() {
-  return nullptr;
+bool TestScreen::IsWindowUnderCursor(gfx::NativeWindow window) {
+  return false;
 }
 
 gfx::NativeWindow TestScreen::GetWindowAtScreenPoint(const gfx::Point& point) {