Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/compiler/parser.cc

Index: third_party/protobuf/src/google/protobuf/compiler/parser.cc
diff --git a/third_party/protobuf/src/google/protobuf/compiler/parser.cc b/third_party/protobuf/src/google/protobuf/compiler/parser.cc
index 09c7a2b65d1a228f004c1d3bf639fdb601f625e6..90ded4de2144b254d6adf7da4c34d03abc6eb90d 100644
--- a/third_party/protobuf/src/google/protobuf/compiler/parser.cc
+++ b/third_party/protobuf/src/google/protobuf/compiler/parser.cc
@@ -525,6 +525,7 @@ bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
   SourceCodeInfo source_code_info;
   source_code_info_ = &source_code_info;
 
+  vector<string> top_doc_comments;
   if (LookingAtType(io::Tokenizer::TYPE_START)) {
     // Advance to first token.
     input_->NextWithComments(NULL, &upcoming_detached_comments_,
@@ -570,7 +571,6 @@ bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
 
   input_ = NULL;
   source_code_info_ = NULL;
-  assert(file != NULL);
   source_code_info.Swap(file->mutable_source_code_info());
   return !had_errors_;
 }
@@ -1630,16 +1630,6 @@ bool Parser::ParseOneof(OneofDescriptorProto* oneof_decl,
       return false;
     }
 
-    if (LookingAt("option")) {
-      LocationRecorder option_location(
-          oneof_location, OneofDescriptorProto::kOptionsFieldNumber);
-      if (!ParseOption(oneof_decl->mutable_options(), option_location,
-                       containing_file, OPTION_STATEMENT)) {
-        return false;
-      }
-      continue;
-    }
-
     // Print a nice error if the user accidentally tries to place a label
     // on an individual member of a oneof.
     if (LookingAt("required") ||