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

extensions/browser/api/system_display/system_display_apitest.cc

Index: extensions/browser/api/system_display/system_display_apitest.cc
diff --git a/extensions/browser/api/system_display/system_display_apitest.cc b/extensions/browser/api/system_display/system_display_apitest.cc
index a9f24c21ea81375f8deb4944a8c83def4074489f..bdca5c36caab18dc8f794aa3923c6ce8dfe37ce6 100644
--- a/extensions/browser/api/system_display/system_display_apitest.cc
+++ b/extensions/browser/api/system_display/system_display_apitest.cc
@@ -40,9 +40,7 @@ class MockScreen : public Screen {
  protected:
   // Overridden from display::Screen:
   gfx::Point GetCursorScreenPoint() override { return gfx::Point(); }
-  gfx::NativeWindow GetWindowUnderCursor() override {
-    return gfx::NativeWindow();
-  }
+  bool IsWindowUnderCursor(gfx::NativeWindow window) override { return false; }
   gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) override {
     return gfx::NativeWindow();
   }