[Cronet] Hook up library loader, system proxy and network change notifier to async api.

components/cronet/android/cronet_url_request_context_adapter.cc

Index: components/cronet/android/cronet_url_request_context_adapter.cc
diff --git a/components/cronet/android/cronet_url_request_context_adapter.cc b/components/cronet/android/cronet_url_request_context_adapter.cc
index eac1ea4f0c35d17b4e7719c70d6e212ab0357a31..c6a4a51602e3eed46b1b6c2ff336d5e521c6b68b 100644
--- a/components/cronet/android/cronet_url_request_context_adapter.cc
+++ b/components/cronet/android/cronet_url_request_context_adapter.cc
@@ -107,7 +107,8 @@ class BasicNetworkDelegate : public net::NetworkDelegateImpl {
 
 namespace cronet {
 
-CronetURLRequestContextAdapter::CronetURLRequestContextAdapter() {
+CronetURLRequestContextAdapter::CronetURLRequestContextAdapter()
+    : is_context_initialized_(false) {
 }
 
 CronetURLRequestContextAdapter::~CronetURLRequestContextAdapter() {
@@ -131,6 +132,11 @@ void CronetURLRequestContextAdapter::Initialize(
                  java_init_network_thread));
 }
 
+void CronetURLRequestContextAdapter::InitRequestContextOnMainThread() {
+  proxy_config_service_.reset(net::ProxyService::CreateSystemProxyConfigService(

[xunjieli, 2015/01/05 14:48:03]

I wonder whether it makes a difference for each context to have its own
ProxyConfigService. Should we make it global across contexts. Any thought?

[mef, 2015/01/05 16:59:21]

CreateSystemProxyConfigService takes io_task_runner, so making global
ProxyConfigService would require global io (aka network) thread. This seems like
a reasonable idea as we don't have any embedder callbacks performed on it, so it
shouldn't block. Matt, WDYT?

[mmenke, 2015/01/05 18:20:39]

I'm not really a big fan of globals, unless they're strictly necessary, or
result in major gains.  Not convinced we need them here.

They also result in bugs (See the bug I filed against Cronet cache startup not
being thread safe...because of a global...)

+      GetNetworkTaskRunner(), NULL));

[xunjieli, 2015/01/05 14:48:03]

I think we moved the task of InitializeOnNetworkThread to the end of
InitRequestContextOnMainThread in url_request_context_adapter.cc, as we need to
wait for proxy_config_service_ to be initialized before we init everything else
on network thread. Maybe we need to do sth similar here?

[mef, 2015/01/05 16:59:21]

Definitely, thanks for spotting that. Done.

+}
+
 void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
     scoped_ptr<URLRequestContextConfig> config,
     const base::Closure& java_init_network_thread) {
@@ -189,6 +195,12 @@ void CronetURLRequestContextAdapter::InitializeOnNetworkThread(
   }
 
   java_init_network_thread.Run();
+
+  is_context_initialized_ = true;
+  while (!tasks_waiting_for_context_.empty()) {
+    tasks_waiting_for_context_.front().Run();
+    tasks_waiting_for_context_.pop();
+  }
 }
 
 void CronetURLRequestContextAdapter::Destroy() {
@@ -208,6 +220,25 @@ net::URLRequestContext* CronetURLRequestContextAdapter::GetURLRequestContext() {
   return context_.get();
 }
 
+void CronetURLRequestContextAdapter::PostTaskToNetworkThread(
+    const tracked_objects::Location& posted_from,
+    const RunAfterContextInitTask& callback) {
+  GetNetworkTaskRunner()->PostTask(
+      posted_from, base::Bind(&CronetURLRequestContextAdapter::
+                                  RunTaskAfterContextInitOnNetworkThread,
+                              base::Unretained(this), callback));
+}
+
+void CronetURLRequestContextAdapter::RunTaskAfterContextInitOnNetworkThread(
+    const RunAfterContextInitTask& callback) {
+  DCHECK(GetNetworkTaskRunner()->BelongsToCurrentThread());
+  if (is_context_initialized_) {
+    callback.Run();
+    return;
+  }
+  tasks_waiting_for_context_.push(callback);
+}
+
 scoped_refptr<base::SingleThreadTaskRunner>
 CronetURLRequestContextAdapter::GetNetworkTaskRunner() const {
   return network_thread_->task_runner();