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..5356a874db46af30f0298824073d4c96e1ecd9d5 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"
@@ -109,7 +110,8 @@ HttpStreamRequest* HttpStreamFactoryImpl::RequestStreamInternal(
   AlternateProtocolInfo alternate =
       GetAlternateProtocolRequestFor(request_info.url, &alternate_url);
   Job* alternate_job = NULL;
-  if (alternate.protocol != UNINITIALIZED_ALTERNATE_PROTOCOL) {
+  if (alternate.protocol != UNINITIALIZED_ALTERNATE_PROTOCOL &&
+      (request_info.load_flags & LOAD_DISABLE_ALTERNATE_PROTOCOLS) == 0) {
     // Never share connection with other jobs for FTP requests.
     DCHECK(!request_info.url.SchemeIs("ftp"));
 
@@ -153,7 +155,8 @@ void HttpStreamFactoryImpl::PreconnectStreams(
   AlternateProtocolInfo alternate =
       GetAlternateProtocolRequestFor(request_info.url, &alternate_url);
   Job* job = NULL;
-  if (alternate.protocol != UNINITIALIZED_ALTERNATE_PROTOCOL) {
+  if (alternate.protocol != UNINITIALIZED_ALTERNATE_PROTOCOL &&
+      (request_info.load_flags & LOAD_DISABLE_ALTERNATE_PROTOCOLS) == 0) {

[Ryan Hamilton, 2015/02/12 23:48:37]

Since this is in two places, could you consider moving this logic down to
HttpStreamFactoryImpl::GetAlternateProtocolRequestFor? (Pass in the load_flags
as an additional argument to that method).

[sclittle, 2015/02/13 19:32:26]

Done.

     HttpRequestInfo alternate_request_info = request_info;
     alternate_request_info.url = alternate_url;
     job = new Job(this, session_, alternate_request_info, priority,