Cronet Java wrappers to fallback to HttpUrlConnection if Cronet is not available.

net/cronet/android/java/src/org/chromium/net/HttpUrlRequestFactory.java

Index: net/cronet/android/java/src/org/chromium/net/HttpUrlRequestFactory.java
diff --git a/net/cronet/android/java/src/org/chromium/net/HttpUrlRequestFactory.java b/net/cronet/android/java/src/org/chromium/net/HttpUrlRequestFactory.java
new file mode 100644
index 0000000000000000000000000000000000000000..9ffd306b8376d36fd65e9b9db1c2cdab643f1ce5
--- /dev/null
+++ b/net/cronet/android/java/src/org/chromium/net/HttpUrlRequestFactory.java
@@ -0,0 +1,105 @@
+// 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.util.Log;
+
+import java.lang.reflect.Constructor;
+import java.nio.channels.WritableByteChannel;
+import java.util.Map;
+
+/**
+ * A factory for {@link HttpUrlRequest}'s, which uses the best HTTP stack
+ * available on the current platform.
+ */
+public abstract class HttpUrlRequestFactory {
+    private static final Object sLock = new Object();
+
+    private static final String TAG = "HttpUrlRequestFactory";
+
+    private static final String CHROMIUM_URL_REQUEST_FACTORY =
+            "org.chromium.net.ChromiumUrlRequestFactory";
+
+    private static HttpUrlRequestFactory sFactory;
+
+    private static HttpUrlRequestFactory getFactory(
+            Context context) {
+        synchronized (sLock) {
+            if (sFactory == null) {
+                try {
+                    Class<? extends HttpUrlRequestFactory> factoryClass =
+                            HttpUrlRequestFactory.class.getClassLoader().
+                                    loadClass(CHROMIUM_URL_REQUEST_FACTORY).
+                                    asSubclass(HttpUrlRequestFactory.class);
+                    Constructor<? extends HttpUrlRequestFactory> constructor =
+                            factoryClass.getConstructor(Context.class);
+                    HttpUrlRequestFactory chromiumFactory =
+                            constructor.newInstance(context);
+                    if (chromiumFactory.isEnabled()) {
+                        sFactory = chromiumFactory;
+                    }
+                } catch (ClassNotFoundException e) {
+                    // Leave as null
+                } catch (Exception e) {
+                    throw new IllegalStateException(
+                            "Cannot instantiate: " +
+                            CHROMIUM_URL_REQUEST_FACTORY,
+                            e);
+                }
+                if (sFactory == null) {
+                    // Default to HttpUrlConnection-based networking.
+                    sFactory = new HttpUrlConnectionUrlRequestFactory(context);
+                }
+                Log.i(TAG, "Using network stack: " + sFactory.getName());
+            }
+            return sFactory;
+        }
+    }
+
+    /**
+     * Creates a new request intended for full-response buffering.
+     */
+    public static HttpUrlRequest newRequest(Context context, String url,
+            int requestPriority, Map<String, String> headers,
+            HttpUrlRequestListener listener) {
+        return getFactory(context).createRequest(url, requestPriority, headers,
+                listener);
+    }
+
+    /**
+     * Creates a new request intended for streaming the response.
+     */
+    public static HttpUrlRequest newRequest(Context context, String url,
+            int requestPriority, Map<String, String> headers,
+            WritableByteChannel channel, HttpUrlRequestListener listener) {
+        return getFactory(context).createRequest(url, requestPriority, headers,
+                channel, listener);
+    }
+
+    /**
+     * Returns true if the factory is enabled.
+     */
+    protected abstract boolean isEnabled();
+
+    /**
+     * Returns a human-readable name of the factory.
+     */
+    protected abstract String getName();
+
+    /**
+     * Creates a new request intended for full-response buffering.
+     */
+    protected abstract HttpUrlRequest createRequest(String url,
+            int requestPriority, Map<String, String> headers,
+            HttpUrlRequestListener listener);
+
+    /**
+     * Creates a new request intended for streaming.
+     */
+    protected abstract HttpUrlRequest createRequest(String url,
+            int requestPriority, Map<String, String> headers,
+            WritableByteChannel channel, HttpUrlRequestListener listener);
+}