[Extensions] Convert APIs to use movable types [4]

chrome/browser/extensions/api/downloads/downloads_api.cc

Index: chrome/browser/extensions/api/downloads/downloads_api.cc
diff --git a/chrome/browser/extensions/api/downloads/downloads_api.cc b/chrome/browser/extensions/api/downloads/downloads_api.cc
index 0a297d2116bd4a67bd2bed82ea1b9fbfa9a1556f..a765a0e4a9d5cd508b24470d6ef85855e75f3582 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api.cc
@@ -988,12 +988,7 @@ bool DownloadsDownloadFunction::RunAsync() {
     download_params->set_prompt(*options.save_as.get());
 
   if (options.headers.get()) {
-    typedef downloads::HeaderNameValuePair HeaderNameValuePair;
-    for (std::vector<linked_ptr<HeaderNameValuePair> >::const_iterator iter =
-         options.headers->begin();
-         iter != options.headers->end();
-         ++iter) {
-      const HeaderNameValuePair& name_value = **iter;
+    for (const downloads::HeaderNameValuePair& name_value : *options.headers) {
       if (!net::HttpUtil::IsValidHeaderName(name_value.name)) {
         error_ = errors::kInvalidHeaderName;
         return false;