skia: Do not include a source file in another source file.

skia/ext/skia_utils_mac_unittest.mm

Index: skia/ext/skia_utils_mac_unittest.mm
diff --git a/skia/ext/skia_utils_mac_unittest.mm b/skia/ext/skia_utils_mac_unittest.mm
index a8f1b70d339de4b669cb5b550cbcd06d397b6a95..27c862bf2fa23e128676acc7a591add51b56be27 100644
--- a/skia/ext/skia_utils_mac_unittest.mm
+++ b/skia/ext/skia_utils_mac_unittest.mm
@@ -2,10 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "skia/ext/skia_utils_mac.mm"
+#include "skia/ext/skia_utils_mac.h"
+
+#import <AppKit/AppKit.h>
 
 #include "base/mac/scoped_nsobject.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/skia/include/core/SkCanvas.h"
 
 namespace {