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

content/common/font_warmup_win_unittest.cc

Index: content/common/font_warmup_win_unittest.cc
diff --git a/content/common/font_warmup_win_unittest.cc b/content/common/font_warmup_win_unittest.cc
index 80eb9e57b1f83f7dc33c94ac27f28dc8f7876a22..c6ba7b1257258ffec87e2b97b445269edcd829d8 100644
--- a/content/common/font_warmup_win_unittest.cc
+++ b/content/common/font_warmup_win_unittest.cc
@@ -256,9 +256,9 @@ TEST(GDIFontEmulationTest, CreateDeleteDCSuccess) {
 
   HDC hdc = CreateCompatibleDC(0);
   EXPECT_NE(hdc, nullptr);
-  EXPECT_EQ(GetEmulatedGdiHandleCountForTesting(), 1);
+  EXPECT_EQ(1u, GetEmulatedGdiHandleCountForTesting());
   EXPECT_TRUE(DeleteDC(hdc));
-  EXPECT_EQ(GetEmulatedGdiHandleCountForTesting(), 0);
+  EXPECT_EQ(0u, GetEmulatedGdiHandleCountForTesting());
 }
 
 TEST(GDIFontEmulationTest, CreateUniqueDCSuccess) {
@@ -274,9 +274,9 @@ TEST(GDIFontEmulationTest, CreateUniqueDCSuccess) {
   EXPECT_NE(hdc2, nullptr);
   EXPECT_NE(hdc1, hdc2);
   EXPECT_TRUE(DeleteDC(hdc2));
-  EXPECT_EQ(GetEmulatedGdiHandleCountForTesting(), 1);
+  EXPECT_EQ(1u, GetEmulatedGdiHandleCountForTesting());
   EXPECT_TRUE(DeleteDC(hdc1));
-  EXPECT_EQ(GetEmulatedGdiHandleCountForTesting(), 0);
+  EXPECT_EQ(0u, GetEmulatedGdiHandleCountForTesting());
 }
 
 TEST(GDIFontEmulationTest, CreateFontSuccess) {
@@ -290,7 +290,7 @@ TEST(GDIFontEmulationTest, CreateFontSuccess) {
   HFONT font = CreateFontIndirectW(&logfont);
   EXPECT_NE(font, nullptr);
   EXPECT_TRUE(DeleteObject(font));
-  EXPECT_EQ(GetEmulatedGdiHandleCountForTesting(), 0);
+  EXPECT_EQ(0u, GetEmulatedGdiHandleCountForTesting());
 }
 
 TEST(GDIFontEmulationTest, CreateFontFailure) {