Inline StringValue into base::Value

chrome/browser/extensions/api/streams_private/streams_private_api.cc

Index: chrome/browser/extensions/api/streams_private/streams_private_api.cc
diff --git a/chrome/browser/extensions/api/streams_private/streams_private_api.cc b/chrome/browser/extensions/api/streams_private/streams_private_api.cc
index dc12dac808f754a699567fba4e96c960674587f7..20dc1afbacf1df8f20930fc7b5259fbfb8f59914 100644
--- a/chrome/browser/extensions/api/streams_private/streams_private_api.cc
+++ b/chrome/browser/extensions/api/streams_private/streams_private_api.cc
@@ -39,7 +39,8 @@ void CreateResponseHeadersDictionary(const net::HttpResponseHeaders* headers,
     if (result->Get(header_name, &existing_value)) {
       base::StringValue* existing_string_value =
           static_cast<base::StringValue*>(existing_value);
-      existing_string_value->GetString()->append(", ").append(header_value);
+      *existing_string_value = base::StringValue(
+          existing_string_value->GetString() + ", " + std::move(header_value));

[brettw, 2017/01/31 22:22:24]

This use of std::move seems not to be helpful to me. I think you should just be
able to do "+ header_value" since it will be passed by const ref into operator+
either way.

[jdoerrie, 2017/02/01 12:36:26]

C++11 introduced overloads for operator+ that take rvalues:
http://en.cppreference.com/w/cpp/string/basic_string/operator%2B

There might be some use for std::move here, but it does feel like a
micro-optimization, so I removed it.

I inlined |existing_string_value|, since the cast to |StringValue| should be a
no-op now and is not needed anymore.

     } else {
       result->SetString(header_name, header_value);
     }