Linux: change protobuf default option to allow building

content/browser/speech/proto/google_streaming_api.proto

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 syntax = "proto2";
-option optimize_for = LITE_RUNTIME;
 
 // TODO(hans): Commented out due to compilation errors.
 // option cc_api_version = 2;
 
 package speech.proto;
 
 // SpeechRecognitionEvent is the only message type sent to client.
 //
 // The first SpeechRecognitionEvent is an empty (default) message to indicate
 // as early as possible that the stream connection has been established.
@@ skipping 40 matching lines @@
 message SpeechRecognitionAlternative {
   // Spoken text.
   optional string transcript = 1;
 
   // The confidence estimate between 0.0 and 1.0.  A higher number means the
   // system is more confident that the recognition is correct.
   // This field is typically provided only for the top hypothesis and only for
   // final results.
   optional float confidence = 2;
 }