IsStringUTF8 unittest and enforcing UTF-8 in JSON deserialization

base/json_reader.cc

Index: base/json_reader.cc
===================================================================
--- base/json_reader.cc	(revision 2506)
+++ base/json_reader.cc	(working copy)
@@ -83,8 +83,11 @@
                              Value** root,
                              bool check_root,
                              bool allow_trailing_comma) {
-  // Assume input is UTF8.  The conversion from UTF8 to wstring removes null
-  // bytes for us (a good thing).
+  // The input must be in UTF-8.
+  if (!IsStringUTF8(json.c_str()))
+    return false;
+  // The conversion from UTF8 to wstring removes null bytes for us
+  // (a good thing).
   std::wstring json_wide(UTF8ToWide(json));
   const wchar_t* json_cstr = json_wide.c_str();