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 e6a337eb07c0a9e826adf7e4efddf2ac3f431b50..f524b998c1056cb7209b8d7c62690778f4701e4a 100644
--- a/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
+++ b/components/cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java
@@ -141,7 +141,11 @@ 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, callback,
+                    executor, httpMethod, requestHeaders);
+        }
     }
 
     @Override
@@ -321,7 +325,7 @@ class CronetUrlRequestContext extends CronetEngine {
      * Mark request as started to prevent shutdown when there are active
      * requests.
      */
-    void onRequestStarted(UrlRequest urlRequest) {
+    void onRequestStarted() {
         mActiveRequestCount.incrementAndGet();
     }
 
@@ -329,7 +333,7 @@ class CronetUrlRequestContext extends CronetEngine {
      * Mark request as completed to allow shutdown when there are no active
      * requests.
      */
-    void onRequestDestroyed(UrlRequest urlRequest) {
+    void onRequestDestroyed() {
         mActiveRequestCount.decrementAndGet();
     }