Fix chromium-style warning after https://codereview.chromium.org/1639623003/

ui/gfx/screen_win_unittest.cc

Index: ui/gfx/screen_win_unittest.cc
diff --git a/ui/gfx/screen_win_unittest.cc b/ui/gfx/screen_win_unittest.cc
index e011c94155a1540f4676e021fe891d18b636e4c6..0be69c359cc100762fca29dd907b4d471ed6f94c 100644
--- a/ui/gfx/screen_win_unittest.cc
+++ b/ui/gfx/screen_win_unittest.cc
@@ -52,7 +52,7 @@ class TestScreenWin : public gfx::ScreenWin {
     UpdateFromDisplayInfos(display_infos);
   }
 
-  ~TestScreenWin() = default;
+  ~TestScreenWin() override = default;
 
  protected:
   // gfx::ScreenWin:
@@ -106,7 +106,7 @@ class TestScreenWin : public gfx::ScreenWin {
     if (search != hwnd_map_.end())
       return MonitorInfoFromScreenRect(search->second);
 
-    EXPECT_EQ(default_options, MONITOR_DEFAULTTOPRIMARY);
+    EXPECT_EQ(default_options, static_cast<DWORD>(MONITOR_DEFAULTTOPRIMARY));
     for (const auto& monitor_info : monitor_infos_) {
       if (monitor_info.rcMonitor.left == 0 &&
           monitor_info.rcMonitor.top == 0) {