Update from https://crrev.com/304418

net/url_request/url_request_context_builder.cc

Index: net/url_request/url_request_context_builder.cc
diff --git a/net/url_request/url_request_context_builder.cc b/net/url_request/url_request_context_builder.cc
index 04c190c4837296307efccbbd27fd441e2ea3663a..41420d503735cb141c74db28a6cbadded42d8f51 100644
--- a/net/url_request/url_request_context_builder.cc
+++ b/net/url_request/url_request_context_builder.cc
@@ -214,7 +214,8 @@ URLRequestContextBuilder::URLRequestContextBuilder()
       ftp_enabled_(false),
 #endif
       http_cache_enabled_(true),
-      throttling_enabled_(false) {
+      throttling_enabled_(false),
+      channel_id_enabled_(true) {
 }
 
 URLRequestContextBuilder::~URLRequestContextBuilder() {}
@@ -296,12 +297,14 @@ URLRequestContext* URLRequestContextBuilder::Build() {
   storage->set_http_auth_handler_factory(http_auth_handler_registry_factory);
   storage->set_cookie_store(new CookieMonster(NULL, NULL));
 
-  // TODO(mmenke):  This always creates a file thread, even when it ends up
-  // not being used.  Consider lazily creating the thread.
-  storage->set_channel_id_service(
-      new ChannelIDService(
-          new DefaultChannelIDStore(NULL),
-          context->GetFileThread()->message_loop_proxy()));
+  if (channel_id_enabled_) {
+    // TODO(mmenke):  This always creates a file thread, even when it ends up
+    // not being used.  Consider lazily creating the thread.
+    storage->set_channel_id_service(
+        new ChannelIDService(
+            new DefaultChannelIDStore(NULL),
+            context->GetFileThread()->message_loop_proxy()));
+  }
 
   storage->set_transport_security_state(new net::TransportSecurityState());
   if (!transport_security_persister_path_.empty()) {