[Embedded Test Server] Enable handler HandleEchoHeader echoing multiple headers

net/test/embedded_test_server/default_handlers.cc

Index: net/test/embedded_test_server/default_handlers.cc
diff --git a/net/test/embedded_test_server/default_handlers.cc b/net/test/embedded_test_server/default_handlers.cc
index 16c2487742e2520e2f0d980e06eb8e1965dddc26..85ed95b39c948b91c99c9c6f09140cbc78ac241f 100644
--- a/net/test/embedded_test_server/default_handlers.cc
+++ b/net/test/embedded_test_server/default_handlers.cc
@@ -70,7 +70,7 @@ std::unique_ptr<HttpResponse> HandleCacheTime(const HttpRequest& request) {
   return std::move(http_response);
 }
 
-// /echoheader | /echoheadercache
+// /echoheader?HEADERS | /echoheadercache?HEADERS
 // Responds with the headers echoed in the message body.
 // echoheader does not cache the results, while echoheadercache does.
 std::unique_ptr<HttpResponse> HandleEchoHeader(const std::string& url,
@@ -82,15 +82,22 @@ std::unique_ptr<HttpResponse> HandleEchoHeader(const std::string& url,
   std::unique_ptr<BasicHttpResponse> http_response(new BasicHttpResponse);
 
   GURL request_url = request.GetURL();
+  std::string content;
   if (request_url.has_query()) {
-    std::string header_name = request_url.query();
-    http_response->AddCustomHeader("Vary", header_name);
-    if (request.headers.find(header_name) != request.headers.end())
-      http_response->set_content(request.headers.at(header_name));
-    else
-      http_response->set_content("None");
+    std::vector<std::string> header_names = base::SplitString(

[svaldez, 2017/02/14 20:23:43]

std::string vary;
std::string content;
RequestQuery headers = ParseQuery(request_url);
for (const auto& header : headers) {
  std::string header_name = header.first;
  std::string header_value = "None";
  if (request.headers.find(header_name) != request.headers.end())
    header_value = request.headers.at(header_name);
  if (!vary.empty())
    vary += ",";
  vary += header_name;
  if (!content.empty())
    content += "\n";
  content += header_value;
}

http_response->AddCustomHeader("Vary", vary);
http_response->set_content(content);

[shenghuazhang, 2017/02/15 01:14:03]

Done.

+        request_url.query(), "&", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
+    for (const auto& header_name : header_names) {
+      http_response->AddCustomHeader("Vary", header_name);
+      if (!content.empty())
+        content += "\n";

[shenghuazhang, 2017/02/14 20:06:42]

I used "\n" to separate the header values here. But not sure if this is a good
separator type?

+      if (request.headers.find(header_name) != request.headers.end())
+        content += request.headers.at(header_name);
+      else
+        content += "None";
+    }
   }
 
+  http_response->set_content(content);
   http_response->set_content_type("text/plain");
   http_response->AddCustomHeader("Cache-Control", cache_control);
   return std::move(http_response);