Update //third_party/protobuf to version 3.

third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs

Index: third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs
diff --git a/third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs b/third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs
new file mode 100644
index 0000000000000000000000000000000000000000..dd485d324aa129f803d7c9e44e97c5acded6641c
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+++ b/third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/TimeExtensions.cs
@@ -0,0 +1,80 @@
+#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;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Google.Protobuf.WellKnownTypes
+{
+    /// <summary>
+    /// Extension methods on BCL time-related types, converting to protobuf types.
+    /// </summary>
+    public static class TimeExtensions
+    {
+        /// <summary>
+        /// Converts the given <see cref="DateTime"/> to a <see cref="Timestamp"/>.
+        /// </summary>
+        /// <param name="dateTime">The date and time to convert to a timestamp.</param>
+        /// <exception cref="ArgumentException">The <paramref name="dateTime"/> value has a <see cref="DateTime.Kind"/>other than <c>Utc</c>.</exception>
+        /// <returns>The converted timestamp.</returns>
+        public static Timestamp ToTimestamp(this DateTime dateTime)
+        {
+            return Timestamp.FromDateTime(dateTime);
+        }
+
+        /// <summary>
+        /// Converts the given <see cref="DateTimeOffset"/> to a <see cref="Timestamp"/>
+        /// </summary>
+        /// <remarks>The offset is taken into consideration when converting the value (so the same instant in time
+        /// is represented) but is not a separate part of the resulting value. In other words, there is no
+        /// roundtrip operation to retrieve the original <c>DateTimeOffset</c>.</remarks>
+        /// <param name="dateTimeOffset">The date and time (with UTC offset) to convert to a timestamp.</param>
+        /// <returns>The converted timestamp.</returns>
+        public static Timestamp ToTimestamp(this DateTimeOffset dateTimeOffset)
+        {
+            return Timestamp.FromDateTimeOffset(dateTimeOffset);
+        }
+
+        /// <summary>
+        /// Converts the given <see cref="TimeSpan"/> to a <see cref="Duration"/>.
+        /// </summary>
+        /// <param name="timeSpan">The time span to convert.</param>
+        /// <returns>The converted duration.</returns>
+        public static Duration ToDuration(this TimeSpan timeSpan)
+        {
+            return Duration.FromTimeSpan(timeSpan);
+        }
+    }
+}