Don’t use using directives (“using namespace”) in tests

util/mach/exc_client_variants_test.cc

Index: util/mach/exc_client_variants_test.cc
diff --git a/util/mach/exc_client_variants_test.cc b/util/mach/exc_client_variants_test.cc
index 3f2926904f67f101e3afb12434c0896526c84f56..0070880a086a483ec9b2e8af7ecadc5ed9a94d73 100644
--- a/util/mach/exc_client_variants_test.cc
+++ b/util/mach/exc_client_variants_test.cc
@@ -27,11 +27,10 @@
 #include "util/test/mac/mach_errors.h"
 #include "util/test/mac/mach_multiprocess.h"
 
+namespace crashpad {
+namespace test {
 namespace {
 
-using namespace crashpad;
-using namespace crashpad::test;
-
 class TestExcClientVariants : public UniversalMachExcServer,
                               public MachMultiprocess {
  public:
@@ -287,3 +286,5 @@ TEST(ExcClientVariants, UniversalExceptionRaise) {
 }
 
 }  // namespace
+}  // namespace test
+}  // namespace crashpad