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

third_party/protobuf/objectivec/GPBExtensionRegistry.h

Index: third_party/protobuf/objectivec/GPBExtensionRegistry.h
diff --git a/third_party/protobuf/objectivec/GPBExtensionRegistry.h b/third_party/protobuf/objectivec/GPBExtensionRegistry.h
deleted file mode 100644
index 0363c70ab8f71c8eb41c71edbf2f74aff4a3152c..0000000000000000000000000000000000000000
--- a/third_party/protobuf/objectivec/GPBExtensionRegistry.h
+++ /dev/null
@@ -1,67 +0,0 @@
-// Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-// 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.
-
-#import <Foundation/Foundation.h>
-
-@class GPBDescriptor;
-@class GPBExtensionDescriptor;
-
-NS_ASSUME_NONNULL_BEGIN
-
-// A table of known extensions, searchable by name or field number.  When
-// parsing a protocol message that might have extensions, you must provide an
-// ExtensionRegistry in which you have registered any extensions that you want
-// to be able to parse.  Otherwise, those extensions will just be treated like
-// unknown fields.
-//
-// The *Root classes provide +extensionRegistry for the extensions defined in a
-// given file *and* all files it imports.  You can also create a
-// GPBExtensionRegistry, and merge those registries to handle parsing extensions
-// defined from non overlapping files.
-//
-//    GPBExtensionRegistry *registry =
-//        [[[MyProtoFileRoot extensionRegistry] copy] autorelease];
-//    [registry addExtension:[OtherMessage neededExtension];  // Not in MyProtoFile
-//    NSError *parseError = nil;
-//    MyMessage *msg = [MyMessage parseData:data
-//                        extensionRegistry:registry
-//                                    error:&parseError];
-//
-@interface GPBExtensionRegistry : NSObject<NSCopying>
-
-- (void)addExtension:(GPBExtensionDescriptor *)extension;
-- (void)addExtensions:(GPBExtensionRegistry *)registry;
-
-- (nullable GPBExtensionDescriptor *)extensionForDescriptor:(GPBDescriptor *)descriptor
-                                                fieldNumber:(NSInteger)fieldNumber;
-
-@end
-
-NS_ASSUME_NONNULL_END