Rewrite std::string("") to std::string(), Linux edition.

net/dns/mock_host_resolver.cc

Index: net/dns/mock_host_resolver.cc
diff --git a/net/dns/mock_host_resolver.cc b/net/dns/mock_host_resolver.cc
index fb038367120de2c4ca3c1343eb6bf90c1cf46510..e6ecf5996827bf3cd30461c255b730327ed571b0 100644
--- a/net/dns/mock_host_resolver.cc
+++ b/net/dns/mock_host_resolver.cc
@@ -256,8 +256,13 @@ void RuleBasedHostResolverProc::AddRuleForAddressFamily(
   DCHECK(!replacement.empty());
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeSystem, host_pattern, address_family, flags,
-            replacement, "", 0);
+  Rule rule(Rule::kResolverTypeSystem,
+            host_pattern,
+            address_family,
+            flags,
+            replacement,
+            std::string(),
+            0);
   rules_.push_back(rule);
 }
 
@@ -286,8 +291,13 @@ void RuleBasedHostResolverProc::AddRuleWithLatency(
   DCHECK(!replacement.empty());
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeSystem, host_pattern, ADDRESS_FAMILY_UNSPECIFIED,
-            flags, replacement, "", latency_ms);
+  Rule rule(Rule::kResolverTypeSystem,
+            host_pattern,
+            ADDRESS_FAMILY_UNSPECIFIED,
+            flags,
+            replacement,
+            std::string(),
+            latency_ms);
   rules_.push_back(rule);
 }
 
@@ -295,8 +305,13 @@ void RuleBasedHostResolverProc::AllowDirectLookup(
     const std::string& host_pattern) {
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeSystem, host_pattern, ADDRESS_FAMILY_UNSPECIFIED,
-            flags, "", "", 0);
+  Rule rule(Rule::kResolverTypeSystem,
+            host_pattern,
+            ADDRESS_FAMILY_UNSPECIFIED,
+            flags,
+            std::string(),
+            std::string(),
+            0);
   rules_.push_back(rule);
 }
 
@@ -304,8 +319,13 @@ void RuleBasedHostResolverProc::AddSimulatedFailure(
     const std::string& host_pattern) {
   HostResolverFlags flags = HOST_RESOLVER_LOOPBACK_ONLY |
       HOST_RESOLVER_DEFAULT_FAMILY_SET_DUE_TO_NO_IPV6;
-  Rule rule(Rule::kResolverTypeFail, host_pattern, ADDRESS_FAMILY_UNSPECIFIED,
-            flags, "", "", 0);
+  Rule rule(Rule::kResolverTypeFail,
+            host_pattern,
+            ADDRESS_FAMILY_UNSPECIFIED,
+            flags,
+            std::string(),
+            std::string(),
+            0);
   rules_.push_back(rule);
 }