Added the support for class level deprecation which will in turn also deprecate…

Added the support for class level deprecation which will in turn also deprecate any fields that are currently using that type

src/google/protobuf/compiler/csharp/csharp_field_base.cc

@@ -126,6 +126,16 @@ void FieldGeneratorBase::AddDeprecatedFlag(io::Printer* printer) {
   {
     printer->Print("[global::System.ObsoleteAttribute]\n");
   }
+  else 
+  {
+    if (descriptor_->type() == FieldDescriptor::TYPE_MESSAGE) 
+    {
+      if (descriptor_->message_type()->options().deprecated())
+      {
+        printer->Print("[global::System.ObsoleteAttribute]\n");
+      }
+    }
+  }
 }
 
 void FieldGeneratorBase::AddPublicMemberAttributes(io::Printer* printer) {

src/google/protobuf/compiler/csharp/csharp_message.cc

@@ -98,12 +98,21 @@ const std::vector<const FieldDescriptor*>& MessageGenerator::fields_by_number()
   return fields_by_number_;
 }
 
+void MessageGenerator::AddDeprecatedFlag(io::Printer* printer) {
+  if (descriptor_->options().deprecated())
+  {
+    printer->Print("[global::System.ObsoleteAttribute]\n");
+  }
+}
+
 void MessageGenerator::Generate(io::Printer* printer) {
   map<string, string> vars;
   vars["class_name"] = class_name();
   vars["access_level"] = class_access_level();
 
   WriteMessageDocComment(printer, descriptor_);
+  AddDeprecatedFlag(printer);
+  
   printer->Print(
     vars,
     "$access_level$ sealed partial class $class_name$ : pb::IMessage<$class_name$> {\n");
@@ -115,6 +124,7 @@ void MessageGenerator::Generate(io::Printer* printer) {
 	  "private static readonly pb::MessageParser<$class_name$> _parser = new pb::MessageParser<$class_name$>(() => new $class_name$());\n");
 
   WriteGeneratedCodeAttributes(printer);
+
   printer->Print(
 	  vars,
 	  "public static pb::MessageParser<$class_name$> Parser { get { return _parser; } }\n\n");

src/google/protobuf/compiler/csharp/csharp_message.h

@@ -69,6 +69,8 @@ class MessageGenerator : public SourceGeneratorBase {
 
   bool HasNestedGeneratedTypes();
 
+  void AddDeprecatedFlag(io::Printer* printer);
+  
   std::string class_name();
   std::string full_class_name();