clang/win: Let remaining chromium_code targets build with -Wextra.

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 2bb4f7b4313f5cd88267d695676d8679e7eefa2e..5e6f9615ce175c3620c13a63317b88f8935139a0 100644
--- a/ui/gfx/screen_win_unittest.cc
+++ b/ui/gfx/screen_win_unittest.cc
@@ -56,7 +56,7 @@ TEST_F(ScreenWinTest, SingleDisplay1x) {
   std::vector<gfx::Display> displays =
       ScreenWin::GetDisplaysForMonitorInfos(monitor_infos);
 
-  ASSERT_EQ(1, displays.size());
+  ASSERT_EQ(1u, displays.size());
   EXPECT_EQ(gfx::Rect(0, 0, 1920, 1200), displays[0].bounds());
   EXPECT_EQ(gfx::Rect(0, 0, 1920, 1100), displays[0].work_area());
 }
@@ -71,7 +71,7 @@ TEST_F(ScreenWinTest, SingleDisplay2x) {
   std::vector<gfx::Display> displays =
       ScreenWin::GetDisplaysForMonitorInfos(monitor_infos);
 
-  ASSERT_EQ(1, displays.size());
+  ASSERT_EQ(1u, displays.size());
   EXPECT_EQ(gfx::Rect(0, 0, 960, 600), displays[0].bounds());
   EXPECT_EQ(gfx::Rect(0, 0, 960, 550), displays[0].work_area());
 }