Added DISABLE_ALTERNATE_PROTOCOLS load flag, and use it for DRP probe.

net/http/http_stream_factory_impl.cc

Index: net/http/http_stream_factory_impl.cc
diff --git a/net/http/http_stream_factory_impl.cc b/net/http/http_stream_factory_impl.cc
index 235122d2e834ae363f77203bc88277c5ad2c96e5..b92247b62be8d8242bb275b71a76b1cc07ee1057 100644
--- a/net/http/http_stream_factory_impl.cc
+++ b/net/http/http_stream_factory_impl.cc
@@ -9,6 +9,7 @@
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
+#include "net/base/load_flags.h"
 #include "net/base/net_log.h"
 #include "net/base/net_util.h"
 #include "net/http/http_network_session.h"
@@ -106,8 +107,8 @@ HttpStreamRequest* HttpStreamFactoryImpl::RequestStreamInternal(
                                  net_log);
 
   GURL alternate_url;
-  AlternateProtocolInfo alternate =
-      GetAlternateProtocolRequestFor(request_info.url, &alternate_url);
+  AlternateProtocolInfo alternate = GetAlternateProtocolRequestFor(
+      request_info.url, request_info.load_flags, &alternate_url);
   Job* alternate_job = NULL;
   if (alternate.protocol != UNINITIALIZED_ALTERNATE_PROTOCOL) {
     // Never share connection with other jobs for FTP requests.
@@ -150,8 +151,8 @@ void HttpStreamFactoryImpl::PreconnectStreams(
     const SSLConfig& proxy_ssl_config) {
   DCHECK(!for_websockets_);
   GURL alternate_url;
-  AlternateProtocolInfo alternate =
-      GetAlternateProtocolRequestFor(request_info.url, &alternate_url);
+  AlternateProtocolInfo alternate = GetAlternateProtocolRequestFor(
+      request_info.url, request_info.load_flags, &alternate_url);
   Job* job = NULL;
   if (alternate.protocol != UNINITIALIZED_ALTERNATE_PROTOCOL) {
     HttpRequestInfo alternate_request_info = request_info;
@@ -173,6 +174,7 @@ const HostMappingRules* HttpStreamFactoryImpl::GetHostMappingRules() const {
 
 AlternateProtocolInfo HttpStreamFactoryImpl::GetAlternateProtocolRequestFor(
     const GURL& original_url,
+    int load_flags,
     GURL* alternate_url) {
   const AlternateProtocolInfo kNoAlternateProtocol;
 
@@ -182,6 +184,9 @@ AlternateProtocolInfo HttpStreamFactoryImpl::GetAlternateProtocolRequestFor(
   if (original_url.SchemeIs("ftp"))
     return kNoAlternateProtocol;
 
+  if (load_flags & LOAD_DISABLE_ALTERNATE_PROTOCOLS)
+    return kNoAlternateProtocol;
+
   HostPortPair origin = HostPortPair::FromURL(original_url);
   HttpServerProperties& http_server_properties =
       *session_->http_server_properties();