Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/csharp/CHANGES.txt

-===============================================================================
-Welcome to the C# port of Google Protocol Buffers, written by Jon Skeet
-(skeet@pobox.com) based on the work of many talented people.
-
-===============================================================================
-RELEASE NOTES - Code imported into Google's main protobuf repository
-===============================================================================
-
-Everything below note this represents history of protobuf-csharp-port project
-before the code was merged into csharp/ subtree of GitHub google/protobuf
-repository.
-Frozen legacy version of the original project is available in
-https://github.com/jskeet/protobuf-csharp-port.
-
-===============================================================================
-RELEASE NOTES - Version 2.4.1.555
-===============================================================================
-
-Changes:
-- Upgrade solution format to Visual Studio 2012.
-- Add the ability to print a builder (not just a message)
-- TextGenerator introduces a new overload of PrintTo
-- Munge protoc's error format into a VS-C#-compatible output format.
-- Work to make ProtoGen clone that acts as a protoc.exe plugin.
-- Added the AllowPartiallyTrustedCallers attribute
-- Optimized enum parsing.
-
-Fixes:
-- Fix for bug in limited input stream's Position, Introduced Position on 
-  output stream
-- Fix for writing a character to a JSON output overflows allocated buffer
-- Optimize FromBase64String to return Empty when presented with empty string.
-- Use string.Concat instead of operator to avoid potential import problems
-- Issue 81: quoting for NUnit parameters.
-- Issue 56: NuGet package is noisy
-- Issue 70: Portable library project has some invalid Nunit-based code.
-- Issue 71: CodedInputStream.ReadBytes go to slow path unnecessarily
-- Issue 84: warning CS0219: The variable `size' is assigned but never used
-
-===============================================================================
-RELEASE NOTES - Version 2.4.1.521
-===============================================================================
-
-Changes:
-- Add generated_code_attributes option, defaulted to false
-- Added support for Portable library
-- Added 'Unsafe' static type in ByteString to allow direct buffer access
-
-Fixes:
-- Issue 50: The XML serializer will fail to deserialize a message with empty 
-  child message
-- Issue 45: Use of 'item' as a field name causes AmbiguousMatchException
-- Issue 49: Generated nested static Types class should be partial
-- Issue 38: Disable CLSCompliant warnings (3021)
-- Issue 40: proto_path does not work for command-line file names
-- Issue 54: should retire all bytes in buffer (bufferSize)
-- Issue 43: Fix to correct identical 'umbrella_classname' options from trying 
-  to write to the same filename.
-
-===============================================================================
-RELEASE NOTES - Version 2.4.1.473
-===============================================================================
-
-Features:
-- Added option service_generator_type to control service generation with
-  NONE, GENERIC, INTERFACE, or IRPCDISPATCH
-- Added interfaces IRpcDispatch and IRpcServerStub to provide for blocking
-  services and implementations.
-- Added ProtoGen.exe command-line argument "--protoc_dir=" to specify the 
-  location of protoc.exe.
-- Extracted interfaces for ICodedInputStream and ICodedOutputStream to allow
-  custom implementation of writers with both speed and size optimizations.
-- Addition of the "Google.ProtoBuffers.Serialization" assembly to support
-  reading and writing messages to/from XML, JSON, IDictionary<,> and others.
-- Several performance related fixes and tweeks
-- Issue 3:      Add option to mark generated code with attribute
-- Issue 20:     Support for decorating classes [Serializable]
-- Issue 21:     Decorate fields with [deprecated=true] as [System.Obsolete]
-- Issue 22:     Reusable Builder classes
-- Issue 24:     Support for using Json/Xml formats with ICodedInputStream
-- Issue 25: Added support for NuGet packages
-- Issue 31: Upgraded protoc.exe and descriptor to 2.4.1
-
-Fixes:
-- Issue 13:     Message with Field same name as message causes uncompilable .cs
-- Issue 16:     Does not integrate well with other tooling
-- Issue 19:     Support for negative enum values
-- Issue 26:     AddRange in GeneratedBuilder iterates twice.
-- Issue 27:     Remove XML documentation output from test projects to clear 
-  warnings/errors.
-- Issue 28: Circular message dependencies result in null default values for 
-  Message fields.
-- Issue 29: Message classes generated have a public default constructor.  You
-  can disable private ctor generation with the option generate_private_ctor.
-- Issue 35: Fixed a bug in ProtoGen handling of arguments with trailing \
-- Big-endian support for float, and double on Silverlight
-- Packed and Unpacked parsing allow for all repeated, as per version 2.3
-- Fix for leaving Builder a public ctor on internal classes for use with
-  generic "where T: new()" constraints.
-
-Other:
-- Changed the code signing key to a privately held key
-- Reformatted all code and line-endings to C# defaults
-- Reworking of performance benchmarks to produce reliable results, option /v2
-- Issue 34: Silverlight assemblies are now unit tested
-
-===============================================================================
-RELEASE NOTES - Version 2.3.0.277
-===============================================================================
-
-Features:
-- Added cls_compliance option to generate attributes indicating 
-  non-CLS-compliance.
-- Added file_extension option to control the generated output file's extension.
-- Added umbrella_namespace option to place the umbrella class into a nested
-  namespace to address issues with proto files having the same name as a 
-  message it contains.
-- Added output_directory option to set the output path for the source file(s).
-- Added ignore_google_protobuf option to avoid generating code for includes 
-  from the google.protobuf package.
-- Added the LITE framework (Google.ProtoBuffersLite.dll) and the ability to
-  generate code with "option optimize_for = LITE_RUNTIME;".
-- Added ability to invoke protoc.exe from within ProtoGen.exe.
-- Upgraded to protoc.exe (2.3) compiler.
-
-Fixes:
-- Issue 9:      Class cannot be static and sealed error
-- Issue 12:     default value for enumerate fields must be filled out
-
-Other:
-- Rewrite of build using MSBbuild instead of NAnt
-- Moved to NUnit Version 2.2.8.0
-- Changed to using secure .snk for releases
-
-===============================================================================
-RELEASE NOTES - Version 0.9.1
-===============================================================================
-
-Fixes:
-- issue 10:     Incorrect encoding of packed fields when serialized
-
-===============================================================================
-RELEASE NOTES - Version 0.9.0
-===============================================================================
-
-- Initial release
-
-===============================================================================