Cleanup: Pass std::string as const reference if possible

url/gurl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifdef WIN32
 #include <windows.h>
 #else
 #include <pthread.h>
 #endif
 
@@ skipping 80 matching lines @@
 GURL::GURL(const char* canonical_spec,
            size_t canonical_spec_len,
            const url::Parsed& parsed,
            bool is_valid)
     : spec_(canonical_spec, canonical_spec_len),
       is_valid_(is_valid),
       parsed_(parsed) {
   InitializeFromCanonicalSpec();
 }
 
-GURL::GURL(std::string canonical_spec, const url::Parsed& parsed, bool is_valid)
-    : is_valid_(is_valid),
+GURL::GURL(const std::string& canonical_spec,
+           const url::Parsed& parsed,
+           bool is_valid)
+    : spec_(canonical_spec),
+      is_valid_(is_valid),
       parsed_(parsed) {
-  spec_.swap(canonical_spec);
   InitializeFromCanonicalSpec();
 }
 
+GURL::GURL(std::string&& canonical_spec,
+           const url::Parsed& parsed,
+           bool is_valid) noexcept
+    : spec_(std::move(canonical_spec)),
+      is_valid_(is_valid),
+      parsed_(parsed) {
+  InitializeFromCanonicalSpec();
+}
+
 template<typename STR>
 void GURL::InitCanonical(const STR& input_spec, bool trim_path_end) {
   // Reserve enough room in the output for the input, plus some extra so that
   // we have room if we have to escape a few things without reallocating.
   spec_.reserve(input_spec.size() + 32);
   url::StdStringCanonOutput output(&spec_);
   is_valid_ = url::Canonicalize(
       input_spec.data(), static_cast<int>(input_spec.length()), trim_path_end,
       NULL, &output, &parsed_);
 
@@ skipping 412 matching lines @@
 void GURL::Swap(GURL* other) {
   spec_.swap(other->spec_);
   std::swap(is_valid_, other->is_valid_);
   std::swap(parsed_, other->parsed_);
   inner_url_.swap(other->inner_url_);
 }
 
 std::ostream& operator<<(std::ostream& out, const GURL& url) {
   return out << url.possibly_invalid_spec();
 }