[Cronet] add a test assertion in UploadDataProvidersTest.java

components/cronet/android/test/javatests/src/org/chromium/net/UploadDataProvidersTest.java

 // Copyright 2016 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.os.ParcelFileDescriptor;
 import android.os.StrictMode;
 import android.test.suitebuilder.annotation.SmallTest;
@@ skipping 206 matching lines @@
         UrlRequest.Builder builder =
                 new UrlRequest.Builder(NativeTestServer.getRedirectToEchoBody(), callback,
                         callback.getExecutor(), mTestFramework.mCronetEngine);
         builder.addHeader("Content-Type", "useless/string");
         byte[] uploadData = LOREM.getBytes("UTF-8");
         int offset = 5;
         byte[] uploadDataWithPadding = new byte[uploadData.length + offset];
         System.arraycopy(uploadData, 0, uploadDataWithPadding, offset, uploadData.length);
         UploadDataProvider dataProvider =
                 UploadDataProviders.create(uploadDataWithPadding, offset, uploadData.length);
+        assertEquals(uploadData.length, dataProvider.getLength());
         builder.setUploadDataProvider(dataProvider, callback.getExecutor());
         UrlRequest urlRequest = builder.build();
         urlRequest.start();
         callback.blockForDone();
         assertEquals(200, callback.mResponseInfo.getHttpStatusCode());
         assertEquals(LOREM, callback.mResponseAsString);
     }
 }