base/json: Get rid of static initializer in JSONReader.

base/json/json_reader.h

Index: base/json/json_reader.h
diff --git a/base/json/json_reader.h b/base/json/json_reader.h
index 39927dee9a1eb9c02bc08802780af06b75d53025..3a9390695d4146cbaf0ae934513a73a7987f840a 100644
--- a/base/json/json_reader.h
+++ b/base/json/json_reader.h
@@ -193,6 +193,8 @@ class BASE_EXPORT JSONReader {
   // line and column are determined and added into the final message.
   void SetErrorCode(const JsonParseError error, const wchar_t* error_pos);
 
+  const Token* kInvalidToken;
+
   // Pointer to the starting position in the input string.
   const wchar_t* start_pos_;