Update third_party/protobuf to protobuf-v3.0.0-beta-3

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

Index: third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs
diff --git a/third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs b/third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs
index 2972b34601c8fe9d563ab3a7ec4c041a8235d895..a235ecefa6f4c2aa7588498aaa628b327bf300c5 100644
--- a/third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs
+++ b/third_party/protobuf/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs
@@ -30,8 +30,8 @@ namespace Google.Protobuf.WellKnownTypes {
             "cHJvdG8z"));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
-          new pbr::GeneratedCodeInfo(null, new pbr::GeneratedCodeInfo[] {
-            new pbr::GeneratedCodeInfo(typeof(global::Google.Protobuf.WellKnownTypes.SourceContext), global::Google.Protobuf.WellKnownTypes.SourceContext.Parser, new[]{ "FileName" }, null, null, null)
+          new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
+            new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.WellKnownTypes.SourceContext), global::Google.Protobuf.WellKnownTypes.SourceContext.Parser, new[]{ "FileName" }, null, null, null)
           }));
     }
     #endregion
@@ -79,7 +79,7 @@ namespace Google.Protobuf.WellKnownTypes {
     public string FileName {
       get { return fileName_; }
       set {
-        fileName_ = pb::Preconditions.CheckNotNull(value, "value");
+        fileName_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
       }
     }