Initial implementation of CronetBidirectionalStream.

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

Index: components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
diff --git a/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java b/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
index da864df6ec05231bf33a3c033fcb3f1985b2a2f7..c2cebf1fca743cdc845f24cb9f8dbf6d75e3f11e 100644
--- a/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
+++ b/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
@@ -160,7 +160,11 @@ class CronetUrlRequestContext extends CronetEngine {
     BidirectionalStream createBidirectionalStream(String url, BidirectionalStream.Callback callback,
             Executor executor, String httpMethod, List<Map.Entry<String, String>> requestHeaders,
             @BidirectionalStream.Builder.StreamPriority int priority) {
-        throw new UnsupportedOperationException();
+        synchronized (mLock) {
+            checkHaveAdapter();
+            return new CronetBidirectionalStream(this, mUrlRequestContextAdapter, url, priority,
+                    callback, executor, httpMethod, requestHeaders);
+        }
     }
 
     @Override
@@ -360,7 +364,7 @@ class CronetUrlRequestContext extends CronetEngine {
      * Mark request as started to prevent shutdown when there are active
      * requests.
      */
-    void onRequestStarted(UrlRequest urlRequest) {
+    void onRequestStarted() {
         mActiveRequestCount.incrementAndGet();
     }
 
@@ -368,7 +372,7 @@ class CronetUrlRequestContext extends CronetEngine {
      * Mark request as finished to allow shutdown when there are no active
      * requests.
      */
-    void onRequestDestroyed(UrlRequest urlRequest) {
+    void onRequestDestroyed() {
         mActiveRequestCount.decrementAndGet();
     }