Add OAuth2 authentication for some voice transcription requests.

content/browser/speech/speech_recognition_engine.h

Index: content/browser/speech/speech_recognition_engine.h
diff --git a/content/browser/speech/speech_recognition_engine.h b/content/browser/speech/speech_recognition_engine.h
index 73ba26ec7e50236b0caae1619a6eb83f3cb887e2..b756833876b4cace085dece95792e2f4e6666d2d 100644
--- a/content/browser/speech/speech_recognition_engine.h
+++ b/content/browser/speech/speech_recognition_engine.h
@@ -59,6 +59,8 @@ class SpeechRecognitionEngine {
     std::string origin_url;
     int audio_sample_rate;
     int audio_num_bits_per_sample;
+    std::string auth_token;
+    std::string auth_scope;
   };
 
   virtual ~SpeechRecognitionEngine() {}