Update //third_party/protobuf to version 3.

third_party/protobuf/objectivec/GPBWireFormat.h

 // 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.
 
-// Author: robinson@google.com (Will Robinson)
+#import "GPBRuntimeTypes.h"
 
+CF_EXTERN_C_BEGIN
 
-package google.protobuf.internal;
+NS_ASSUME_NONNULL_BEGIN
 
+typedef enum {
+  GPBWireFormatVarint = 0,
+  GPBWireFormatFixed64 = 1,
+  GPBWireFormatLengthDelimited = 2,
+  GPBWireFormatStartGroup = 3,
+  GPBWireFormatEndGroup = 4,
+  GPBWireFormatFixed32 = 5,
+} GPBWireFormat;
 
-message TopLevelMessage {
-  optional ExtendedMessage submessage = 1;
-}
+enum {
+  GPBWireFormatMessageSetItem = 1,
+  GPBWireFormatMessageSetTypeId = 2,
+  GPBWireFormatMessageSetMessage = 3
+};
 
+uint32_t GPBWireFormatMakeTag(uint32_t fieldNumber, GPBWireFormat wireType)
+    __attribute__((const));
+GPBWireFormat GPBWireFormatGetTagWireType(uint32_t tag) __attribute__((const));
+uint32_t GPBWireFormatGetTagFieldNumber(uint32_t tag) __attribute__((const));
 
-message ExtendedMessage {
-  extensions 1 to max;
-}
+GPBWireFormat GPBWireFormatForType(GPBDataType dataType, BOOL isPacked)
+    __attribute__((const));
 
+#define GPBWireFormatMessageSetItemTag \
+  (GPBWireFormatMakeTag(GPBWireFormatMessageSetItem, GPBWireFormatStartGroup))
+#define GPBWireFormatMessageSetItemEndTag \
+  (GPBWireFormatMakeTag(GPBWireFormatMessageSetItem, GPBWireFormatEndGroup))
+#define GPBWireFormatMessageSetTypeIdTag \
+  (GPBWireFormatMakeTag(GPBWireFormatMessageSetTypeId, GPBWireFormatVarint))
+#define GPBWireFormatMessageSetMessageTag               \
+  (GPBWireFormatMakeTag(GPBWireFormatMessageSetMessage, \
+                        GPBWireFormatLengthDelimited))
 
-message ForeignMessage {
-  optional int32 foreign_message_int = 1;
-}
+NS_ASSUME_NONNULL_END
 
-
-extend ExtendedMessage {
-  optional int32 optional_int_extension = 1;
-  optional ForeignMessage optional_message_extension = 2;
-
-  repeated int32 repeated_int_extension = 3;
-  repeated ForeignMessage repeated_message_extension = 4;
-}
+CF_EXTERN_C_END