Update //third_party/protobuf to version 3.

third_party/protobuf/csharp/src/Google.Protobuf/Reflection/IDescriptor.cs

+#region Copyright notice and license
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// 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
 
-// Author: robinson@google.com (Will Robinson)
+namespace Google.Protobuf.Reflection
+{
+    /// <summary>
+    /// Interface implemented by all descriptor types.
+    /// </summary>
+    public interface IDescriptor
+    {
+        /// <summary>
+        /// Returns the name of the entity (message, field etc) being described.
+        /// </summary>
+        string Name { get; }
 
+        /// <summary>
+        /// Returns the fully-qualified name of the entity being described.
+        /// </summary>
+        string FullName { get; }
 
-package google.protobuf.internal;
-
-// A message where tag numbers are listed out of order, to allow us to test our
-// canonicalization of serialized output, which should always be in tag order.
-// We also mix in some extensions for extra fun.
-message OutOfOrderFields {
-  optional   sint32 optional_sint32   =  5;
-  extensions 4 to 4;
-  optional   uint32 optional_uint32   =  3;
-  extensions 2 to 2;
-  optional    int32 optional_int32    =  1;
-};
-
-
-extend OutOfOrderFields {
-  optional   uint64 optional_uint64   =  4;
-  optional    int64 optional_int64    =  2;
-}
+        /// <summary>
+        /// Returns the descriptor for the .proto file that this entity is part of.
+        /// </summary>
+        FileDescriptor File { get; }
+    }    
+}