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

components/cronet/android/cronet_loader.cc

Index: components/cronet/android/cronet_loader.cc
diff --git a/components/cronet/android/cronet_loader.cc b/components/cronet/android/cronet_loader.cc
index 3929b6cb516af3639a92de51f03f51aabe0fdc02..34799c0edc41da76eead8456e1a2f45cfce08eae 100644
--- a/components/cronet/android/cronet_loader.cc
+++ b/components/cronet/android/cronet_loader.cc
@@ -6,12 +6,16 @@
 #include "base/android/jni_android.h"
 #include "base/android/jni_registrar.h"
 #include "base/at_exit.h"
+#include "base/message_loop/message_loop.h"
 #include "components/cronet/android/chromium_url_request.h"
 #include "components/cronet/android/chromium_url_request_context.h"
 #include "components/cronet/android/cronet_url_request.h"
 #include "components/cronet/android/cronet_url_request_context.h"
 #include "components/cronet/android/histogram_manager.h"
+#include "jni/CronetLibraryLoader_jni.h"
 #include "net/android/net_jni_registrar.h"
+#include "net/android/network_change_notifier_factory_android.h"
+#include "net/base/network_change_notifier.h"
 #include "url/android/url_jni_registrar.h"
 #include "url/url_util.h"
 
@@ -26,6 +30,7 @@ const base::android::RegistrationMethod kCronetRegisteredMethods[] = {
     {"BaseAndroid", base::android::RegisterJni},
     {"ChromiumUrlRequest", cronet::ChromiumUrlRequestRegisterJni},
     {"ChromiumUrlRequestContext", cronet::ChromiumUrlRequestContextRegisterJni},
+    {"CronetLibraryLoader", cronet::RegisterNativesImpl},
     {"CronetUrlRequest", cronet::CronetUrlRequestRegisterJni},
     {"CronetUrlRequestContext", cronet::CronetUrlRequestContextRegisterJni},
     {"HistogramManager", cronet::HistogramManagerRegisterJni},
@@ -34,6 +39,11 @@ const base::android::RegistrationMethod kCronetRegisteredMethods[] = {
 };
 
 base::AtExitManager* g_at_exit_manager = NULL;
+// MessageLoop on the main thread, which is where objects that receive Java
+// notifications generally live.
+base::MessageLoop* g_main_message_loop = nullptr;
+
+net::NetworkChangeNotifier* g_network_change_notifier = nullptr;
 
 }  // namespace
 
@@ -69,4 +79,27 @@ void CronetOnUnLoad(JavaVM* jvm, void* reserved) {
   }
 }
 
+jlong CronetInitOnMainThread(JNIEnv* env, jclass jcaller, jobject jcontext) {
+  // Set application context.
+  base::android::ScopedJavaLocalRef<jobject> scoped_context(env, jcontext);
+  base::android::InitApplicationContext(env, scoped_context);
+#if !defined(USE_ICU_ALTERNATIVES_ON_ANDROID)
+  base::i18n::InitializeICU();

[mmenke, 2015/01/08 19:06:16]

Don't think we need to do this twice, and we're already doing this in OnLoad.

[mef, 2015/01/08 21:17:02]

Done.

+#endif
+
+  if (!base::MessageLoop::current()) {
+    DCHECK(!g_main_message_loop);
+    g_main_message_loop = new base::MessageLoopForUI();
+    base::MessageLoopForUI::current()->Start();

[mmenke, 2015/01/08 19:06:16]

What code depends on the main Java thread having a MessageLoop?  Think we always
jump to it Java-side.

[mef, 2015/01/08 21:17:02]

Helen will correct me if I'm wrong, but my understanding is that it is needed
for auto proxy service, which gets/handles system notifications on main thread.

[xunjieli, 2015/01/08 21:34:24]

Yes, we need to set up a message loop for the main UI thread. It is needed for
both ProxyConfigServiceAndroid and NetworkChangeNotifierAndroid behind the
scene. 

Taken from network_change_notifier_android: "// - The calls to the Java side
(stateful) object must be performed from a
//   single thread. This object happens to be a singleton which is used on the
//   application side on the main thread. Therefore all the method calls from
//   the native NetworkChangeNotifierAndroid class to its Java counterpart are
//   performed on the main thread."

+  }
+  DCHECK_EQ(g_main_message_loop, base::MessageLoop::current());
+  if (!g_network_change_notifier) {
+    net::NetworkChangeNotifier::SetFactory(
+        new net::NetworkChangeNotifierFactoryAndroid());
+    g_network_change_notifier = net::NetworkChangeNotifier::Create();
+  }
+
+  return 0;
+}
+
 }  // namespace cronet