Rewrite base::JSONReader to be 35-40% faster, depending on the input string.

net/test/spawner_communicator.cc

Index: net/test/spawner_communicator.cc
diff --git a/net/test/spawner_communicator.cc b/net/test/spawner_communicator.cc
index 8b454f096dc239b7bab379a8eb711ecc79a55f67..a1fa18ac203512524dcda14c47fce0829b09011d 100644
--- a/net/test/spawner_communicator.cc
+++ b/net/test/spawner_communicator.cc
@@ -321,9 +321,7 @@ bool SpawnerCommunicator::StartServer(const std::string& arguments,
     return false;
 
   // Check whether the data returned from spawner server is JSON-formatted.
-  base::JSONReader json_reader;
-  scoped_ptr<base::Value> value(json_reader.JsonToValue(server_return_data,
-                                                        true, false));
+  scoped_ptr<base::Value> value(base::JSONReader::Read(server_return_data));
   if (!value.get() || !value->IsType(base::Value::TYPE_DICTIONARY)) {
     LOG(ERROR) << "Invalid server data: " << server_return_data.c_str();
     return false;