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

net/http/http_auth_gssapi_posix_unittest.cc

Index: net/http/http_auth_gssapi_posix_unittest.cc
diff --git a/net/http/http_auth_gssapi_posix_unittest.cc b/net/http/http_auth_gssapi_posix_unittest.cc
index cbf4d3dde0601f47d66d72c8957f7e1ac4fca40a..1c3d12b6c291915a89105db5e46f51543e4a0add 100644
--- a/net/http/http_auth_gssapi_posix_unittest.cc
+++ b/net/http/http_auth_gssapi_posix_unittest.cc
@@ -76,7 +76,7 @@ TEST(HttpAuthGSSAPIPOSIXTest, GSSAPIStartup) {
   // TODO(ahendrickson): Manipulate the libraries and paths to test each of the
   // libraries we expect, and also whether or not they have the interface
   // functions we want.
-  scoped_ptr<GSSAPILibrary> gssapi(new GSSAPISharedLibrary(""));
+  scoped_ptr<GSSAPILibrary> gssapi(new GSSAPISharedLibrary(std::string()));
   DCHECK(gssapi.get());
   EXPECT_TRUE(gssapi.get()->Init());
 }