Use std::string instead of mojo::String in //net.

chrome/browser/net/utility_process_mojo_proxy_resolver_factory.cc

Index: chrome/browser/net/utility_process_mojo_proxy_resolver_factory.cc
diff --git a/chrome/browser/net/utility_process_mojo_proxy_resolver_factory.cc b/chrome/browser/net/utility_process_mojo_proxy_resolver_factory.cc
index 8850788fa3a59178dac0569ff393e816f68d7b18..9714ab8a133cfeb4b57cfc80eed506e8b6dead75 100644
--- a/chrome/browser/net/utility_process_mojo_proxy_resolver_factory.cc
+++ b/chrome/browser/net/utility_process_mojo_proxy_resolver_factory.cc
@@ -67,7 +67,7 @@ void UtilityProcessMojoProxyResolverFactory::CreateProcessAndConnect() {
 
 std::unique_ptr<base::ScopedClosureRunner>
 UtilityProcessMojoProxyResolverFactory::CreateResolver(
-    const mojo::String& pac_script,
+    const std::string& pac_script,
     mojo::InterfaceRequest<net::interfaces::ProxyResolver> req,
     net::interfaces::ProxyResolverFactoryRequestClientPtr client) {
   DCHECK(thread_checker_.CalledOnValidThread());