[Chromecast] Enable QUIC for Chromecast.

chromecast/browser/url_request_context_factory.cc

Index: chromecast/browser/url_request_context_factory.cc
diff --git a/chromecast/browser/url_request_context_factory.cc b/chromecast/browser/url_request_context_factory.cc
index ef726e6dd507f6c9f0611c7b02387bd197f94422..1691517d59b453a94c90080607075cce9df7481c 100644
--- a/chromecast/browser/url_request_context_factory.cc
+++ b/chromecast/browser/url_request_context_factory.cc
@@ -165,8 +165,8 @@ URLRequestContextFactory::URLRequestContextFactory()
       system_network_delegate_(CastNetworkDelegate::Create()),
       system_dependencies_initialized_(false),
       main_dependencies_initialized_(false),
-      media_dependencies_initialized_(false) {
-}
+      media_dependencies_initialized_(false),
+      enable_quic_(true) {}
 
 URLRequestContextFactory::~URLRequestContextFactory() {
 }
@@ -307,6 +307,7 @@ void URLRequestContextFactory::InitializeMediaContextDependencies(
 void URLRequestContextFactory::PopulateNetworkSessionParams(
     bool ignore_certificate_errors,
     net::HttpNetworkSession::Params* params) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
   params->host_resolver = host_resolver_.get();
   params->cert_verifier = cert_verifier_.get();
   params->channel_id_service = channel_id_service_.get();
@@ -318,6 +319,9 @@ void URLRequestContextFactory::PopulateNetworkSessionParams(
   params->http_server_properties = http_server_properties_.get();
   params->ignore_certificate_errors = ignore_certificate_errors;
   params->proxy_service = proxy_service_.get();
+
+  LOG(INFO) << "Set HttpNetworkSessionParams.enable_quic = " << enable_quic_;

[halliwell, 2017/01/27 04:32:53]

how frequently does this get logged?  Just want to make sure it's not going to
be spammy.

[mbjorge, 2017/01/27 06:22:20]

It'll get logged a max of 3 times, once for each of the
Main/System/MediaContextGetters when they get created.

+  params->enable_quic = enable_quic_;
 }
 
 net::URLRequestContext* URLRequestContextFactory::CreateSystemRequestContext() {
@@ -427,5 +431,47 @@ void URLRequestContextFactory::InitializeNetworkDelegates() {
   LOG(INFO) << "Initialized system network delegate.";
 }
 
+void URLRequestContextFactory::DisableQuic() {
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&URLRequestContextFactory::DisableQuicOnBrowserIOThread,
+                 base::Unretained(this)));

[halliwell, 2017/01/27 04:32:53]

Should this be done with weak ptr, or is there a guarantee that this object
lives until posted task is run?

[mbjorge, 2017/01/27 06:22:20]

URLRequestContextFactory is owned by CastContentBrowserClient, so it will live
as long as that does, which to my understanding was the entire life of
cast_shell, since it's getting created/owned by CastMainDelegate in
cast_main.cc, so it should outlive basically everything.

I don't see harm in adding it though, so I'm happy to add it if it makes it more
obviously safe to a reader. I've tried just adding a comment for now describing
why it should be safe. 

[halliwell, 2017/01/27 18:35:35]

That's fine, looks good.

+}
+
+void URLRequestContextFactory::DisableQuicOnBrowserIOThread() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  if (!enable_quic_)
+    return;
+
+  LOG(INFO) << "Disabled QUIC.";
+
+  // Disable QUIC for any new URLContextGetter that gets created.

[halliwell, 2017/01/27 04:32:53]

this and the next 3 comments don't add value (what the code does is
self-evident)

[mbjorge, 2017/01/27 06:22:20]

done

+  enable_quic_ = false;
+
+  // Disable QUIC for the main URLContext.
+  if (main_getter_) {
+    main_getter_->GetURLRequestContext()
+        ->http_transaction_factory()
+        ->GetSession()
+        ->DisableQuic();
+  }
+
+  // Disable QUIC for the system URLContext.
+  if (system_getter_) {
+    system_getter_->GetURLRequestContext()
+        ->http_transaction_factory()
+        ->GetSession()
+        ->DisableQuic();
+  }
+
+  // Disable QUIC for the media URLContext.
+  if (media_getter_) {
+    media_getter_->GetURLRequestContext()
+        ->http_transaction_factory()
+        ->GetSession()
+        ->DisableQuic();
+  }
+}
+
 }  // namespace shell
 }  // namespace chromecast