Update //third_party/protobuf to version 3.

third_party/protobuf/csharp/src/Google.Protobuf/MessageExtensions.cs

Index: third_party/protobuf/csharp/src/Google.Protobuf/MessageExtensions.cs
diff --git a/third_party/protobuf/csharp/src/Google.Protobuf/MessageExtensions.cs b/third_party/protobuf/csharp/src/Google.Protobuf/MessageExtensions.cs
new file mode 100644
index 0000000000000000000000000000000000000000..d2d057c0c9204f42be8bbcd681b0f1a8892e4954
--- /dev/null
+++ b/third_party/protobuf/csharp/src/Google.Protobuf/MessageExtensions.cs
@@ -0,0 +1,157 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using System.IO;
+
+namespace Google.Protobuf
+{
+    /// <summary>
+    /// Extension methods on <see cref="IMessage"/> and <see cref="IMessage{T}"/>.
+    /// </summary>
+    public static class MessageExtensions
+    {
+        /// <summary>
+        /// Merges data from the given byte array into an existing message.
+        /// </summary>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="data">The data to merge, which must be protobuf-encoded binary data.</param>
+        public static void MergeFrom(this IMessage message, byte[] data)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            Preconditions.CheckNotNull(data, "data");
+            CodedInputStream input = new CodedInputStream(data);
+            message.MergeFrom(input);
+            input.CheckReadEndOfStreamTag();
+        }
+
+        /// <summary>
+        /// Merges data from the given byte string into an existing message.
+        /// </summary>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="data">The data to merge, which must be protobuf-encoded binary data.</param>
+        public static void MergeFrom(this IMessage message, ByteString data)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            Preconditions.CheckNotNull(data, "data");
+            CodedInputStream input = data.CreateCodedInput();
+            message.MergeFrom(input);
+            input.CheckReadEndOfStreamTag();
+        }
+
+        /// <summary>
+        /// Merges data from the given stream into an existing message.
+        /// </summary>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="input">Stream containing the data to merge, which must be protobuf-encoded binary data.</param>
+        public static void MergeFrom(this IMessage message, Stream input)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            Preconditions.CheckNotNull(input, "input");
+            CodedInputStream codedInput = new CodedInputStream(input);
+            message.MergeFrom(codedInput);
+            codedInput.CheckReadEndOfStreamTag();
+        }
+
+        /// <summary>
+        /// Merges length-delimited data from the given stream into an existing message.
+        /// </summary>
+        /// <remarks>
+        /// The stream is expected to contain a length and then the data. Only the amount of data
+        /// specified by the length will be consumed.
+        /// </remarks>
+        /// <param name="message">The message to merge the data into.</param>
+        /// <param name="input">Stream containing the data to merge, which must be protobuf-encoded binary data.</param>
+        public static void MergeDelimitedFrom(this IMessage message, Stream input)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            Preconditions.CheckNotNull(input, "input");
+            int size = (int) CodedInputStream.ReadRawVarint32(input);
+            Stream limitedStream = new LimitedInputStream(input, size);
+            message.MergeFrom(limitedStream);
+        }
+
+        /// <summary>
+        /// Converts the given message into a byte array in protobuf encoding.
+        /// </summary>
+        /// <param name="message">The message to convert.</param>
+        /// <returns>The message data as a byte array.</returns>
+        public static byte[] ToByteArray(this IMessage message)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            byte[] result = new byte[message.CalculateSize()];
+            CodedOutputStream output = new CodedOutputStream(result);
+            message.WriteTo(output);
+            output.CheckNoSpaceLeft();
+            return result;
+        }
+
+        /// <summary>
+        /// Writes the given message data to the given stream in protobuf encoding.
+        /// </summary>
+        /// <param name="message">The message to write to the stream.</param>
+        /// <param name="output">The stream to write to.</param>
+        public static void WriteTo(this IMessage message, Stream output)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            Preconditions.CheckNotNull(output, "output");
+            CodedOutputStream codedOutput = new CodedOutputStream(output);
+            message.WriteTo(codedOutput);
+            codedOutput.Flush();
+        }
+
+        /// <summary>
+        /// Writes the length and then data of the given message to a stream.
+        /// </summary>
+        /// <param name="message">The message to write.</param>
+        /// <param name="output">The output stream to write to.</param>
+        public static void WriteDelimitedTo(this IMessage message, Stream output)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            Preconditions.CheckNotNull(output, "output");
+            CodedOutputStream codedOutput = new CodedOutputStream(output);
+            codedOutput.WriteRawVarint32((uint)message.CalculateSize());
+            message.WriteTo(codedOutput);
+            codedOutput.Flush();
+        }
+
+        /// <summary>
+        /// Converts the given message into a byte string in protobuf encoding.
+        /// </summary>
+        /// <param name="message">The message to convert.</param>
+        /// <returns>The message data as a byte string.</returns>
+        public static ByteString ToByteString(this IMessage message)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            return ByteString.AttachBytes(message.ToByteArray());
+        }        
+    }
+}