Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/message_lite.h

Index: third_party/protobuf/src/google/protobuf/message_lite.h
diff --git a/third_party/protobuf/src/google/protobuf/message_lite.h b/third_party/protobuf/src/google/protobuf/message_lite.h
index 1ec3068cfad192f70c23ec38ce5ab227d0e82464..4c16f4c0572be88df0a702e8a5455d0ec78fc385 100644
--- a/third_party/protobuf/src/google/protobuf/message_lite.h
+++ b/third_party/protobuf/src/google/protobuf/message_lite.h
@@ -1,6 +1,6 @@
 // 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
@@ -41,9 +41,10 @@
 
 #include <google/protobuf/stubs/common.h>
 
+
 namespace google {
 namespace protobuf {
-
+  class Arena;
 namespace io {
   class CodedInputStream;
   class CodedOutputStream;
@@ -88,6 +89,27 @@ class LIBPROTOBUF_EXPORT MessageLite {
   // caller.
   virtual MessageLite* New() const = 0;
 
+  // Construct a new instance on the arena. Ownership is passed to the caller
+  // if arena is a NULL. Default implementation for backwards compatibility.
+  virtual MessageLite* New(::google::protobuf::Arena* arena) const;
+
+  // Get the arena, if any, associated with this message. Virtual method
+  // required for generic operations but most arena-related operations should
+  // use the GetArenaNoVirtual() generated-code method. Default implementation
+  // to reduce code size by avoiding the need for per-type implementations when
+  // types do not implement arena support.
+  virtual ::google::protobuf::Arena* GetArena() const { return NULL; }
+
+  // Get a pointer that may be equal to this message's arena, or may not be. If
+  // the value returned by this method is equal to some arena pointer, then this
+  // message is on that arena; however, if this message is on some arena, this
+  // method may or may not return that arena's pointer. As a tradeoff, this
+  // method may be more efficient than GetArena(). The intent is to allow
+  // underlying representations that use e.g. tagged pointers to sometimes store
+  // the arena pointer directly, and sometimes in a more indirect way, and allow
+  // a fastpath comparison against the arena pointer when it's easy to obtain.
+  virtual void* GetMaybeArenaPointer() const { return GetArena(); }
+
   // Clear all fields of the message and set them to their default values.
   // Clear() avoids freeing memory, assuming that any memory allocated
   // to hold parts of the message will be needed again to hold the next
@@ -109,11 +131,13 @@ class LIBPROTOBUF_EXPORT MessageLite {
 
   // Parsing ---------------------------------------------------------
   // Methods for parsing in protocol buffer format.  Most of these are
-  // just simple wrappers around MergeFromCodedStream().
+  // just simple wrappers around MergeFromCodedStream().  Clear() will be called
+  // before merging the input.
 
-  // Fill the message with a protocol buffer parsed from the given input
-  // stream.  Returns false on a read error or if the input is in the
-  // wrong format.
+  // Fill the message with a protocol buffer parsed from the given input stream.
+  // Returns false on a read error or if the input is in the wrong format.  A
+  // successful return does not indicate the entire input is consumed, ensure
+  // you call ConsumedEntireMessage() to check that if applicable.
   bool ParseFromCodedStream(io::CodedInputStream* input);
   // Like ParseFromCodedStream(), but accepts messages that are missing
   // required fields.
@@ -132,7 +156,11 @@ class LIBPROTOBUF_EXPORT MessageLite {
   // missing required fields.
   bool ParsePartialFromBoundedZeroCopyStream(io::ZeroCopyInputStream* input,
                                              int size);
-  // Parse a protocol buffer contained in a string.
+  // Parses a protocol buffer contained in a string. Returns true on success.
+  // This function takes a string in the (non-human-readable) binary wire
+  // format, matching the encoding output by MessageLite::SerializeToString().
+  // If you'd like to convert a human-readable string into a protocol buffer
+  // object, see google::protobuf::TextFormat::ParseFromString().
   bool ParseFromString(const string& data);
   // Like ParseFromString(), but accepts messages that are missing
   // required fields.
@@ -210,6 +238,9 @@ class LIBPROTOBUF_EXPORT MessageLite {
   // Computes the serialized size of the message.  This recursively calls
   // ByteSize() on all embedded messages.  If a subclass does not override
   // this, it MUST override SetCachedSize().
+  //
+  // ByteSize() is generally linear in the number of fields defined for the
+  // proto.
   virtual int ByteSize() const = 0;
 
   // Serializes the message without recomputing the size.  The message must