[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";
 
+    /**
+     * Synchronize access to mUrlRequestContextAdapter and shutdown routine.
+     */
+    private final Object mLock = new Object();
+
     private long mUrlRequestContextAdapter = 0;
     private Thread mNetworkThread;
     private AtomicInteger mActiveRequestCount = new AtomicInteger(0);
 
     public CronetUrlRequestContext(Context context,
                                    UrlRequestContextConfig config) {
+        CronetLibraryLoader.ensureInitialized(context, config);
         nativeSetMinLogLevel(getLoggingLevel());
+        final String configString = config.toString();

[xunjieli, 2015/01/12 15:12:34]

nit: could you make config.toString() inline?

[mef, 2015/01/12 17:19:56]

Done.

         mUrlRequestContextAdapter = nativeCreateRequestContextAdapter(
-                context, config.toString());
+                context, configString);
         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() {
+                // mUrlRequestContextAdapter is guaranteed to exist until
+                // initialization on main and network threads completes and
+                // initNetworkThread is called back on network thread.
+                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,
                 UrlRequest.REQUEST_PRIORITY_MEDIUM, listener, executor);
     }
 
     @Override
     public boolean isEnabled() {
         return Build.VERSION.SDK_INT >= 14;
     }
 
     @Override
     public String getVersionString() {
         return "Cronet/" + Version.getVersion();
     }
 
     @Override
     public void shutdown() {
-        if (mActiveRequestCount.get() != 0) {
-            throw new IllegalStateException(
-                    "Cannot shutdown with active requests.");
+        synchronized (mLock) {
+            if (mNetworkThread == null) {
+                throw new IllegalStateException(
+                        "Context is not fully initialized.");
+            }
+            if (mUrlRequestContextAdapter == 0) {
+                throw new IllegalStateException(
+                        "Context is already shutdown.");
+            }
+            if (mActiveRequestCount.get() != 0) {
+                throw new IllegalStateException(
+                        "Cannot shutdown with active requests.");
+            }
+            // Destroying adapter stops the network thread, so it cannot be
+            // called on network thread.
+            if (Thread.currentThread() == mNetworkThread) {
+                throw new IllegalThreadStateException(
+                        "Cannot shutdown from network thread.");
+            }
+            nativeDestroyRequestContextAdapter(mUrlRequestContextAdapter);
+            mUrlRequestContextAdapter = 0;
         }
-        // Destroying adapter stops the network thread, so it cannot be called
-        // on network thread.
-        if (Thread.currentThread() == mNetworkThread) {
-            throw new IllegalThreadStateException(
-                    "Cannot shutdown from network thread.");
-        }
-        nativeDestroyRequestContextAdapter(mUrlRequestContextAdapter);
-        mUrlRequestContextAdapter = 0;
     }
 
     @Override
     public void startNetLogToFile(String fileName) {
         nativeStartNetLogToFile(mUrlRequestContextAdapter, fileName);
     }
 
     @Override
     public void stopNetLog() {
         nativeStopNetLog(mUrlRequestContextAdapter);
@@ skipping 52 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);
 }