Make the default alternate protcol probability threshold 1, not 0.

net/http/http_server_properties_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/http/http_server_properties_impl.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 
 namespace net {
 
 namespace {
 
 const uint64 kBrokenAlternateProtocolDelaySecs = 300;
 
 }  // namespace
 
 HttpServerPropertiesImpl::HttpServerPropertiesImpl()
     : spdy_servers_map_(SpdyServerHostPortMap::NO_AUTO_EVICT),
       alternate_protocol_map_(AlternateProtocolMap::NO_AUTO_EVICT),
       alternate_protocol_experiment_(
           ALTERNATE_PROTOCOL_NOT_PART_OF_EXPERIMENT),
       spdy_settings_map_(SpdySettingsMap::NO_AUTO_EVICT),
-      alternate_protocol_probability_threshold_(0),
+      alternate_protocol_probability_threshold_(1),
       weak_ptr_factory_(this) {
   canoncial_suffixes_.push_back(".c.youtube.com");
   canoncial_suffixes_.push_back(".googlevideo.com");
   canoncial_suffixes_.push_back(".googleusercontent.com");
 }
 
 HttpServerPropertiesImpl::~HttpServerPropertiesImpl() {
 }
 
 void HttpServerPropertiesImpl::InitializeSpdyServers(
@@ skipping 151 matching lines @@
   // Cache the data.
   spdy_servers_map_.Put(spdy_server, support_spdy);
 }
 
 bool HttpServerPropertiesImpl::HasAlternateProtocol(
     const HostPortPair& server) {
   if (g_forced_alternate_protocol)
     return true;
   AlternateProtocolMap::const_iterator it = alternate_protocol_map_.Get(server);
   if (it != alternate_protocol_map_.end() &&
-      it->second.probability > alternate_protocol_probability_threshold_) {
+      it->second.probability >= alternate_protocol_probability_threshold_) {
     return true;
   }
 
   return GetCanonicalHost(server) != canonical_host_to_origin_map_.end();
 }
 
 std::string HttpServerPropertiesImpl::GetCanonicalSuffix(
     const HostPortPair& server) {
   // If this host ends with a canonical suffix, then return the canonical
   // suffix.
@@ skipping 266 matching lines @@
   base::TimeDelta delay = when > now ? when - now : base::TimeDelta();
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(
           &HttpServerPropertiesImpl::ExpireBrokenAlternateProtocolMappings,
           weak_ptr_factory_.GetWeakPtr()),
       delay);
 }
 
 }  // namespace net