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

components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java

 // 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.
 
 package org.chromium.net;
 
 import android.content.Context;
 import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
 import android.os.Process;
 import android.util.Log;
 
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
 
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * UrlRequest context using Chromium HTTP stack implementation.
  */
 @JNINamespace("cronet")
 public class CronetUrlRequestContext extends UrlRequestContext  {
     private static final int LOG_NONE = 3;  // LOG(FATAL), no VLOG.
     private static final int LOG_DEBUG = -1;  // LOG(FATAL...INFO), VLOG(1)
     private static final int LOG_VERBOSE = -2;  // LOG(FATAL...INFO), VLOG(2)
     static final String LOG_TAG = "ChromiumNetwork";
 
     private long mUrlRequestContextAdapter = 0;
     private Thread mNetworkThread;
     private AtomicInteger mActiveRequestCount = new AtomicInteger(0);
 
     public CronetUrlRequestContext(Context context,
                                    UrlRequestContextConfig config) {
+        CronetLibraryLoader.loadAndInitialize(context, config);

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

Maybe rename "loadAndInitialize" to sth like "initIfNeeded"? since
CronetLibraryLoader only loads and initializes when this function is invoked the
first time.

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

Done. ensureInitialized seems to be commonly used in Chrome.

         nativeSetMinLogLevel(getLoggingLevel());
         mUrlRequestContextAdapter = nativeCreateRequestContextAdapter(
                 context, config.toString());
         if (mUrlRequestContextAdapter == 0) {
             throw new NullPointerException("Context Adapter creation failed");
         }
+        // Post a task to UI thread to init native Chromium URLRequestContext.
+        // TODO(xunjieli): This constructor is not supposed to be invoked on
+        // the main thread. Consider making the following code into a blocking
+        // API to handle the case where we are already on main thread.
+        Runnable task = new Runnable() {
+            public void run() {
+                nativeInitRequestContextOnMainThread(
+                        mUrlRequestContextAdapter);
+            }
+        };
+        new Handler(Looper.getMainLooper()).post(task);
     }
 
     @Override
     public UrlRequest createRequest(String url, UrlRequestListener listener,
                                     Executor executor) {
         if (mUrlRequestContextAdapter == 0) {
             throw new IllegalStateException(
                     "Cannot create requests on shutdown context.");
         }
         return new CronetUrlRequest(this, mUrlRequestContextAdapter, url,
@@ skipping 89 matching lines @@
 
     private native void nativeDestroyRequestContextAdapter(
             long urlRequestContextAdapter);
 
     private native void nativeStartNetLogToFile(
             long urlRequestContextAdapter, String fileName);
 
     private native void nativeStopNetLog(long urlRequestContextAdapter);
 
     private native int nativeSetMinLogLevel(int loggingLevel);
+
+    private native void nativeInitRequestContextOnMainThread(
+            long urlRequestContextAdapter);
 }