Remove a few un-necessary string copies in net/

BUG=233164
R=pliard@chromium.org

Review URL: https://chromiumcodereview.appspot.com/14315009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@195035 0039d316-1c4b-4281-b951-d872f2087c98

net/http/http_request_headers.cc

@@ -85,16 +85,16 @@ void HttpRequestHeaders::SetHeader(const base::StringPiece& key,
                                    const base::StringPiece& value) {
   HeaderVector::iterator it = FindHeader(key);
   if (it != headers_.end())
-    it->value = value.as_string();
+    it->value.assign(value.data(), value.size());
   else
-    headers_.push_back(HeaderKeyValuePair(key.as_string(), value.as_string()));
+    headers_.push_back(HeaderKeyValuePair(key, value));
 }
 
 void HttpRequestHeaders::SetHeaderIfMissing(const base::StringPiece& key,
                                             const base::StringPiece& value) {
   HeaderVector::iterator it = FindHeader(key);
   if (it == headers_.end())
-    headers_.push_back(HeaderKeyValuePair(key.as_string(), value.as_string()));
+    headers_.push_back(HeaderKeyValuePair(key, value));
 }
 
 void HttpRequestHeaders::RemoveHeader(const base::StringPiece& key) {