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

client/capture_context_mac_test.cc

Index: client/capture_context_mac_test.cc
diff --git a/client/capture_context_mac_test.cc b/client/capture_context_mac_test.cc
index 53d08e264b482d761cdd1b925aafde0cd3f3f6cf..3dc0ba8dabc1e80e21c4c238cf27396a822e58c7 100644
--- a/client/capture_context_mac_test.cc
+++ b/client/capture_context_mac_test.cc
@@ -22,10 +22,10 @@
 #include "build/build_config.h"
 #include "gtest/gtest.h"
 
+namespace crashpad {
+namespace test {
 namespace {
 
-using namespace crashpad;
-
 // If the context structure has fields that tell whether it’s valid, such as
 // magic numbers or size fields, sanity-checks those fields for validity with
 // fatal gtest assertions. For other fields, where it’s possible to reason about
@@ -152,3 +152,5 @@ TEST(CaptureContextMac, CaptureContext) {
 }
 
 }  // namespace
+}  // namespace test
+}  // namespace crashpad