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

net/http/http_security_headers_unittest.cc

Index: net/http/http_security_headers_unittest.cc
diff --git a/net/http/http_security_headers_unittest.cc b/net/http/http_security_headers_unittest.cc
index a142486e9323832fdb4c02ed8f84b8ff14fb36aa..4f1e5804745c2864243c36b36f7e112ff9980ac4 100644
--- a/net/http/http_security_headers_unittest.cc
+++ b/net/http/http_security_headers_unittest.cc
@@ -51,7 +51,8 @@ TEST_F(HttpSecurityHeadersTest, BogusHeaders) {
   base::Time expiry = now;
   bool include_subdomains = false;
 
-  EXPECT_FALSE(ParseHSTSHeader(now, "", &expiry, &include_subdomains));
+  EXPECT_FALSE(
+      ParseHSTSHeader(now, std::string(), &expiry, &include_subdomains));
   EXPECT_FALSE(ParseHSTSHeader(now, "    ", &expiry, &include_subdomains));
   EXPECT_FALSE(ParseHSTSHeader(now, "abc", &expiry, &include_subdomains));
   EXPECT_FALSE(ParseHSTSHeader(now, "  abc", &expiry, &include_subdomains));
@@ -135,7 +136,8 @@ static void TestBogusPinsHeaders(HashValueTag tag) {
   std::string good_pin = GetTestPin(2, tag);
   std::string backup_pin = GetTestPin(4, tag);
 
-  EXPECT_FALSE(ParseHPKPHeader(now, "", chain_hashes, &expiry, &hashes));
+  EXPECT_FALSE(
+      ParseHPKPHeader(now, std::string(), chain_hashes, &expiry, &hashes));
   EXPECT_FALSE(ParseHPKPHeader(now, "    ", chain_hashes, &expiry, &hashes));
   EXPECT_FALSE(ParseHPKPHeader(now, "abc", chain_hashes, &expiry, &hashes));
   EXPECT_FALSE(ParseHPKPHeader(now, "  abc", chain_hashes, &expiry, &hashes));