json_schema_compiler: Use std::vector<char> for binary values.

content/public/browser/speech_recognition_session_preamble.h

Index: content/public/browser/speech_recognition_session_preamble.h
diff --git a/content/public/browser/speech_recognition_session_preamble.h b/content/public/browser/speech_recognition_session_preamble.h
index 2f4e6085dcfb83ef4c381e89113ac2cc3b17639f..589953184d5ce1fd1d473cb63c3d8c26e727d5f3 100644
--- a/content/public/browser/speech_recognition_session_preamble.h
+++ b/content/public/browser/speech_recognition_session_preamble.h
@@ -5,7 +5,7 @@
 #ifndef CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNITION_SESSION_PREAMBLE_H_
 #define CONTENT_PUBLIC_BROWSER_SPEECH_RECOGNITION_SESSION_PREAMBLE_H_
 
-#include <string>
+#include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
@@ -26,7 +26,7 @@ struct CONTENT_EXPORT SpeechRecognitionSessionPreamble
   int sample_depth;
 
   // Audio data, in little-endian samples.
-  std::string sample_data;
+  std::vector<char> sample_data;
 
  private:
   friend class base::RefCounted<SpeechRecognitionSessionPreamble>;