Cronet: Fix CronetUploadTest.testDestroyAdapterBefore* tests.

components/cronet/android/test/src/org/chromium/net/TestUploadDataStreamHandler.java

 // Copyright 2015 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 junit.framework.Assert;
 
@@ skipping 19 matching lines @@
     // If true, init completes synchronously.
     private boolean mInitCompletedSynchronously = false;
     private String mData = "";
 
     public TestUploadDataStreamHandler(final long uploadDataStream) {
         mTestUploadDataStreamHandler =
                 nativeCreateTestUploadDataStreamHandler(uploadDataStream);
     }
 
     public void destroyNativeObjects() {
-        nativeDestroy(mTestUploadDataStreamHandler);
-        mTestUploadDataStreamHandler = 0;
+        if (mTestUploadDataStreamHandler != 0) {
+            nativeDestroy(mTestUploadDataStreamHandler);
+            mTestUploadDataStreamHandler = 0;
+        }
     }
 
     /**
      * Init and returns whether init completes synchronously.
      */
     public boolean init() {
         mData = "";
         nativeInit(mTestUploadDataStreamHandler);
         mWaitInitCalled.block();
         mWaitInitCalled.close();
@@ skipping 109 matching lines @@
     @NativeClassQualifiedName("TestUploadDataStreamHandler")
     private native void nativeCheckReadCallbackNotInvoked(
             long nativePtr);
 
     @NativeClassQualifiedName("TestUploadDataStreamHandler")
     private native void nativeDestroy(long nativePtr);
 
     private native long nativeCreateTestUploadDataStreamHandler(
             long uploadDataStream);
 }