Revert of Stop doing unnecessary UTF-8 to UTF-16 conversions in JSONWriter.

base/json/json_writer.h

 // 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.
 
 #ifndef BASE_JSON_JSON_WRITER_H_
 #define BASE_JSON_JSON_WRITER_H_
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 
 namespace base {
 
 class Value;
 
 class BASE_EXPORT JSONWriter {
  public:
   enum Options {
+    // Do not escape the string, preserving its UTF8 characters. It is useful
+    // if you can pass the resulting string to the JSON parser in binary form
+    // (as UTF8).
+    OPTIONS_DO_NOT_ESCAPE = 1 << 0,
+
     // For values of binary type, the value (and key if within a dictionary)
     // will be omitted from the output.
-    OPTIONS_OMIT_BINARY_VALUES = 1 << 0,
+    OPTIONS_OMIT_BINARY_VALUES = 1 << 1,
 
     // This option instructs the writer to write doubles that have no fractional
     // part as a normal integer (i.e., without using exponential notation
     // or appending a '.0') as long as the value is within the range of a
     // 64-bit int.
-    OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION = 1 << 1,
+    OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION = 1 << 2,
 
     // Return a slightly nicer formatted json string (pads with whitespace to
     // help with readability).
-    OPTIONS_PRETTY_PRINT = 1 << 2,
+    OPTIONS_PRETTY_PRINT = 1 << 3
   };
 
   // Given a root node, generates a JSON string and puts it into |json|.
   // TODO(tc): Should we generate json if it would be invalid json (e.g.,
   // |node| is not a DictionaryValue/ListValue or if there are inf/-inf float
   // values)?
   static void Write(const Value* const node, std::string* json);
 
   // Same as above but with |options| which is a bunch of JSONWriter::Options
   // bitwise ORed together.
   static void WriteWithOptions(const Value* const node, int options,
                                std::string* json);
 
+  // A static, constant JSON string representing an empty array.  Useful
+  // for empty JSON argument passing.
+  static const char* kEmptyArray;
+
  private:
-  JSONWriter(bool omit_binary_values,
+  JSONWriter(bool escape, bool omit_binary_values,
              bool omit_double_type_preservation, bool pretty_print,
              std::string* json);
 
   // Called recursively to build the JSON string.  Whe completed, value is
   // json_string_ will contain the JSON.
   void BuildJSONString(const Value* const node, int depth);
 
+  // Appends a quoted, escaped, version of (UTF-8) str to json_string_.
+  void AppendQuotedString(const std::string& str);
+
   // Adds space to json_string_ for the indent level.
   void IndentLine(int depth);
 
+  bool escape_;
   bool omit_binary_values_;
   bool omit_double_type_preservation_;
   bool pretty_print_;
 
   // Where we write JSON data as we generate it.
   std::string* json_string_;
 
   DISALLOW_COPY_AND_ASSIGN(JSONWriter);
 };
 
 }  // namespace base
 
 #endif  // BASE_JSON_JSON_WRITER_H_