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

tools/on_demand_service_tool.mm

Index: tools/on_demand_service_tool.mm
diff --git a/tools/on_demand_service_tool.mm b/tools/on_demand_service_tool.mm
index 946989c7fa3767dbfa45b93c74b73fcc64c07bec..460f4cd8eda6c814e143f62f06b2e6ac1ea9916d 100644
--- a/tools/on_demand_service_tool.mm
+++ b/tools/on_demand_service_tool.mm
@@ -30,10 +30,9 @@
 #include "util/mac/service_management.h"
 #include "util/stdlib/objc.h"
 
+namespace crashpad {
 namespace {
 
-using namespace crashpad;
-
 void Usage(const std::string& me) {
   fprintf(stderr,
 "Usage: %s -L -l LABEL [OPTION]... COMMAND [ARG]...\n"
@@ -52,9 +51,7 @@ void Usage(const std::string& me) {
   ToolSupport::UsageTail(me);
 }
 
-}  // namespace
-
-int main(int argc, char* argv[]) {
+int OnDemandServiceToolMain(int argc, char* argv[]) {
   const std::string me(basename(argv[0]));
 
   enum Operation {
@@ -190,3 +187,10 @@ int main(int argc, char* argv[]) {
     }
   }
 }
+
+}  // namespace
+}  // namespace crashpad
+
+int main(int argc, char* argv[]) {
+  return crashpad::OnDemandServiceToolMain(argc, argv);
+}