[Cronet] Fix CronetFixedModeOutputStream to not write more bytes than specified

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

Index: components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/QuicUploadTest.java
diff --git a/components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/QuicUploadTest.java b/components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/QuicUploadTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..5f6a205d95359300d764fd803b9ae18c9af277a3
--- /dev/null
+++ b/components/cronet/android/test/javatests/src/org/chromium/net/urlconnection/QuicUploadTest.java
@@ -0,0 +1,75 @@
+// 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.urlconnection;
+
+import android.test.suitebuilder.annotation.SmallTest;
+
+import org.chromium.base.test.util.Feature;
+import org.chromium.net.CronetEngine;
+import org.chromium.net.CronetTestBase;
+import org.chromium.net.CronetTestFramework;
+import org.chromium.net.QuicTestServer;
+import org.json.JSONObject;
+
+import java.io.OutputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Arrays;
+
+/**
+ * Tests HttpURLConnection upload using QUIC.
+ */
+@SuppressWarnings("deprecation")
+public class QuicUploadTest extends CronetTestBase {
+    private CronetTestFramework mTestFramework;
+
+    @Override
+    protected void setUp() throws Exception {
+        super.setUp();
+        // Load library first to create MockCertVerifier.
+        System.loadLibrary("cronet_tests");
+        CronetEngine.Builder builder = new CronetEngine.Builder(getContext());
+
+        QuicTestServer.startQuicTestServer(getContext());
+
+        builder.enableQUIC(true);
+        JSONObject quicParams =
+                new JSONObject().put("host_whitelist", QuicTestServer.getServerHost());
+        JSONObject experimentalOptions = new JSONObject().put("QUIC", quicParams);
+        builder.setExperimentalOptions(experimentalOptions.toString());
+
+        builder.addQuicHint(QuicTestServer.getServerHost(), QuicTestServer.getServerPort(),
+                QuicTestServer.getServerPort());
+
+        builder.setMockCertVerifierForTesting(QuicTestServer.createMockCertVerifier());
+
+        mTestFramework = startCronetTestFrameworkWithUrlAndCronetEngineBuilder(null, builder);
+        registerHostResolver(mTestFramework);
+    }
+
+    @SmallTest
+    @Feature({"Cronet"})
+    @OnlyRunNativeCronet
+    // Regression testing for crbug.com/618872.
+    public void testOneMassiveWrite() throws Exception {
+        String path = "/simple.txt";
+        URL url = new URL(QuicTestServer.getServerURL() + path);
+        HttpURLConnection connection =
+                (HttpURLConnection) mTestFramework.mCronetEngine.openConnection(url);
+        connection.setDoOutput(true);
+        connection.setRequestMethod("POST");
+        // Size is chosen so the last time mBuffer will be written 14831 bytes,
+        // which is larger than the internal QUIC read buffer size of 14520.
+        byte[] largeData = new byte[195055];
+        Arrays.fill(largeData, "a".getBytes("UTF-8")[0]);
+        connection.setFixedLengthStreamingMode(largeData.length);
+        OutputStream out = connection.getOutputStream();
+        // Write everything at one go, so the data is larger than the buffer
+        // used in CronetFixedModeOutputStream.
+        out.write(largeData);
+        assertEquals(200, connection.getResponseCode());
+        connection.disconnect();
+    }
+}