[Cronet] Fix testDestroyUploadDataStreamAdapterOnSucceededCallback flake.

components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestTest.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.os.ConditionVariable;
 import android.test.MoreAsserts;
 import android.test.suitebuilder.annotation.SmallTest;
 import android.util.Log;
@@ skipping 1706 matching lines @@
         final ConditionVariable uploadDataStreamAdapterDestroyed = new ConditionVariable();
         request.setOnDestroyedUploadCallbackForTesting(new Runnable() {
             @Override
             public void run() {
                 uploadDataStreamAdapterDestroyed.open();
             }
         });
 
         request.start();
         uploadDataStreamAdapterDestroyed.block();
+        callback.blockForDone();
 
         assertEquals(200, callback.mResponseInfo.getHttpStatusCode());
         assertEquals("", callback.mResponseAsString);
     }
 
     /*
      * Verifies error codes are passed through correctly.
      */
     @SmallTest
     @Feature({"Cronet"})
@@ skipping 76 matching lines @@
     private String bufferContentsToString(ByteBuffer byteBuffer, int start, int end) {
         // Use a duplicate to avoid modifying byteBuffer.
         ByteBuffer duplicate = byteBuffer.duplicate();
         duplicate.position(start);
         duplicate.limit(end);
         byte[] contents = new byte[duplicate.remaining()];
         duplicate.get(contents);
         return new String(contents);
     }
 }