Make URLRequestContextAdapter initialization asynchronous

components/cronet/android/url_request_context_adapter.cc

 // Copyright 2014 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 "components/cronet/android/url_request_context_adapter.h"
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/single_thread_task_runner.h"
 #include "components/cronet/url_request_context_config.h"
@@ skipping 117 matching lines @@
 
   GetNetworkTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&URLRequestContextAdapter::InitializeURLRequestContext,
                  this,
                  Passed(&config)));
 }
 
 void URLRequestContextAdapter::InitializeURLRequestContext(
     scoped_ptr<URLRequestContextConfig> config) {
+  DCHECK(GetNetworkTaskRunner()->BelongsToCurrentThread());
   // TODO(mmenke):  Add method to have the builder enable SPDY.
   net::URLRequestContextBuilder context_builder;
   context_builder.set_network_delegate(new BasicNetworkDelegate());
   context_builder.set_proxy_config_service(
       new net::ProxyConfigServiceFixed(net::ProxyConfig()));
   config->ConfigureURLRequestContextBuilder(&context_builder);
 
   context_.reset(context_builder.Build());
 
   // Currently (circa M39) enabling QUIC requires setting probability threshold.
@@ skipping 23 matching lines @@
       }
 
       net::HostPortPair quic_hint_host_port_pair(quic_hint.host,
                                                  quic_hint.port);
       context_->http_server_properties()->SetAlternateProtocol(
           quic_hint_host_port_pair,
           static_cast<uint16>(quic_hint.alternate_port),
           net::AlternateProtocol::QUIC,
           1.0f);
     }
+    is_context_initialized_ = true;
+    while (!tasks_waiting_for_context_.empty()) {
+      tasks_waiting_for_context_.front().Run();
+      tasks_waiting_for_context_.pop();
+    }
   }
 
   if (VLOG_IS_ON(2)) {
     net_log_observer_.reset(new NetLogObserver());
     context_->net_log()->AddThreadSafeObserver(net_log_observer_.get(),
                                                net::NetLog::LOG_ALL_BUT_BYTES);
   }
 
   delegate_->OnContextInitialized(this);
 }
 
+void URLRequestContextAdapter::RunTaskAfterContextInit(
+    const RunAfterContextInitTask& callback) {
+  GetNetworkTaskRunner()->PostTask(
+      FROM_HERE,

[mef, 2014/10/10 15:06:27]

I'm a bit concerned that all posted tasks will now come FROM_HERE. Would it make
sense to pass tracked_objects::Location as a parameter?

[xunjieli, 2014/10/10 17:25:45]

Done. Good idea!

+      base::Bind(
+          &URLRequestContextAdapter::RunTaskAfterContextInitOnNetworkThread,
+          this,
+          callback));
+}
+
+void URLRequestContextAdapter::RunTaskAfterContextInitOnNetworkThread(
+    const RunAfterContextInitTask& callback) {
+  DCHECK(GetNetworkTaskRunner()->BelongsToCurrentThread());
+  if (is_context_initialized_) {
+    callback.Run();
+    return;
+  }
+  tasks_waiting_for_context_.push(callback);
+}
+
 URLRequestContextAdapter::~URLRequestContextAdapter() {
+  DCHECK(GetNetworkTaskRunner()->BelongsToCurrentThread());
   if (net_log_observer_) {
     context_->net_log()->RemoveThreadSafeObserver(net_log_observer_.get());
     net_log_observer_.reset();
   }
-  StopNetLog();
+  StopNetLogHelper();
   // TODO(mef): Ensure that |network_thread_| is destroyed properly.
 }
 
 const std::string& URLRequestContextAdapter::GetUserAgent(
     const GURL& url) const {
   return user_agent_;
 }
 
 net::URLRequestContext* URLRequestContextAdapter::GetURLRequestContext() {
+  DCHECK(GetNetworkTaskRunner()->BelongsToCurrentThread());
   if (!context_) {
     LOG(ERROR) << "URLRequestContext is not set up";
   }
   return context_.get();
 }
 
 scoped_refptr<base::SingleThreadTaskRunner>
 URLRequestContextAdapter::GetNetworkTaskRunner() const {
   return network_thread_->message_loop_proxy();
 }
 
 void URLRequestContextAdapter::StartNetLogToFile(const std::string& file_name) {
+  RunTaskAfterContextInit(base::Bind(
+      &URLRequestContextAdapter::StartNetLogToFileHelper, this, file_name));
+}
+
+void URLRequestContextAdapter::StopNetLog() {
+  RunTaskAfterContextInit(
+      base::Bind(&URLRequestContextAdapter::StopNetLogHelper, this));
+}
+
+void URLRequestContextAdapter::StartNetLogToFileHelper(
+    const std::string& file_name) {
+  DCHECK(GetNetworkTaskRunner()->BelongsToCurrentThread());
   // Do nothing if already logging to a file.
   if (net_log_logger_)
     return;
 
   base::FilePath file_path(file_name);
   FILE* file = base::OpenFile(file_path, "w");
   if (!file)
     return;
 
   scoped_ptr<base::Value> constants(net::NetLogLogger::GetConstants());
   net_log_logger_.reset(new net::NetLogLogger(file, *constants));
   net_log_logger_->StartObserving(context_->net_log());
 }
 
-void URLRequestContextAdapter::StopNetLog() {
+void URLRequestContextAdapter::StopNetLogHelper() {
+  DCHECK(GetNetworkTaskRunner()->BelongsToCurrentThread());
   if (net_log_logger_) {
     net_log_logger_->StopObserving();
     net_log_logger_.reset();
   }
 }
 
 void NetLogObserver::OnAddEntry(const net::NetLog::Entry& entry) {
   VLOG(2) << "Net log entry: type=" << entry.type()
           << ", source=" << entry.source().type << ", phase=" << entry.phase();
 }
 
 }  // namespace cronet