Fix a pair of Cronet upload bugs and add tests.

net/test/embedded_test_server/http_request.h

Index: net/test/embedded_test_server/http_request.h
diff --git a/net/test/embedded_test_server/http_request.h b/net/test/embedded_test_server/http_request.h
index 1e849d87d2519f4b8b5a07240c2ac8cc9f9186e6..cb9144b14496e7b6e1eed563a8a4907a06cb7673 100644
--- a/net/test/embedded_test_server/http_request.h
+++ b/net/test/embedded_test_server/http_request.h
@@ -35,6 +35,7 @@ struct HttpRequest {
 
   std::string relative_url;  // Starts with '/'. Example: "/test?query=foo"
   HttpMethod method;
+  std::string method_string;
   std::map<std::string, std::string> headers;
   std::string content;
   bool has_content;