Respect QuicAllowed policy for new streams

chrome/browser/profiles/profile_io_data.cc

Index: chrome/browser/profiles/profile_io_data.cc
diff --git a/chrome/browser/profiles/profile_io_data.cc b/chrome/browser/profiles/profile_io_data.cc
index f5acaf6aa25e5c973a439269282e438a6bb3eeb9..e54729d36c704d329f30f373456f74af12c8baae 100644
--- a/chrome/browser/profiles/profile_io_data.cc
+++ b/chrome/browser/profiles/profile_io_data.cc
@@ -46,6 +46,7 @@
 #include "chrome/browser/policy/policy_helpers.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 #include "chrome/browser/predictors/resource_prefetch_predictor_factory.h"
+#include "chrome/browser/profiles/net_http_session_params_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ssl/chrome_expect_ct_reporter.h"
@@ -470,6 +471,14 @@ void ProfileIOData::InitializeOnUIThread(Profile* profile) {
       &allowed_domains_for_apps_,
       pref_service);
 
+  DCHECK(!net_http_session_params_observer_);
+  NetHttpSessionParamsObserver::UpdateNetParamsCallback
+      update_net_params_callback = base::Bind(
+          &ProfileIOData::UpdateNetParamsOnIOThread, base::Unretained(this));
+  net_http_session_params_observer_ =
+      base::MakeUnique<NetHttpSessionParamsObserver>(
+          pref_service, update_net_params_callback);

[mmenke, 2017/01/09 16:46:04]

I believe this is a bug.  We haven't even created the URLRequestContext by this
point, so this will call post a task to call ApplySettingsOnIOThread(), which
calls  ProfileIOData::UpdateNetParamsOnIOThread, which notices that there's no
URLRequestContext, so it does nothing.  Then we when we actually create the
URLRequestContext, it doesn't pick up on the configuration, and if it's enabled
in IOThread::GetNetworkSessionParams, we're out of luck.

In contravention of what I said over email earlier this morning, I think we're
going to need browser tests for this code, if there's a way to set prefs or
group policies before profile creation.  Too many races, too easy to get wrong.

[pmarko, 2017/01/09 19:53:12]

This was very misleading, sorry about that. I've tried to make this more clear
now. As we're only disabling QUIC now, and disabling it also disables it for
IOThread, both ways work:

(1) URLRequestContext already constructed: QUIC disabled through callback
(2) URLRequestContext not constructed yet: QUIC disabled in IOThread's params_,
which will be used for URLRequestContext construction -> QUIC disabled there.

You're absolutely right that this would not work for re-enabling QUIc, and as
we've discussed, I've made it obvious by naming now that we are not supporting
re-enabling.

+
   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner =
       BrowserThread::GetTaskRunnerForThread(BrowserThread::IO);
 
@@ -926,6 +935,16 @@ std::unique_ptr<net::ClientCertStore> ProfileIOData::CreateClientCertStore() {
 #endif
 }
 
+void ProfileIOData::UpdateNetParamsOnIOThread(
+    net::HttpNetworkSession::ParamsUpdate params_update) {
+  if (!main_request_context_storage_ ||
+      !main_request_context_storage_->http_network_session())
+    return;
+
+  main_request_context_storage_->http_network_session()->UpdateParams(
+      params_update);
+}
+
 void ProfileIOData::set_data_reduction_proxy_io_data(
     std::unique_ptr<data_reduction_proxy::DataReductionProxyIOData>
         data_reduction_proxy_io_data) const {
@@ -1236,6 +1255,7 @@ void ProfileIOData::ShutdownOnUIThread(
   if (chrome_http_user_agent_settings_)
     chrome_http_user_agent_settings_->CleanupOnUIThread();
   incognito_availibility_pref_.Destroy();
+  net_http_session_params_observer_.reset();
 
   if (!context_getters->empty()) {
     if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {