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

base/json/json_writer.h

Index: base/json/json_writer.h
diff --git a/base/json/json_writer.h b/base/json/json_writer.h
index e4a143c77807e78bf84b4804b3bae988c86533bd..94052c8034321dd28e6adf4699029e287eb93a6f 100644
--- a/base/json/json_writer.h
+++ b/base/json/json_writer.h
@@ -17,19 +17,24 @@
 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|.
@@ -43,8 +48,12 @@
   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);
 
@@ -52,9 +61,13 @@
   // 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_;