Mojo C++ bindings: add a new mode to generator to use native STL/WTF types

mojo/public/cpp/bindings/tests/binding_callback_unittest.cc

 // Copyright 2015 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.
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 69 matching lines @@
   // Saves its two input values in member variables and does nothing else.
   void EchoInt(int32_t x, const EchoIntCallback& callback) override {
     last_server_value_seen_ = x;
     *callback_saved_ = callback;
     if (!closure_.is_null()) {
       closure_.Run();
       closure_.Reset();
     }
   }
 
-  void EchoString(const String& a,
+  void EchoString(const std::string& a,
                   const EchoStringCallback& callback) override {
     CHECK(false) << "Not implemented.";
   }
 
-  void EchoStrings(const String& a,
-                   const String& b,
+  void EchoStrings(const std::string& a,
+                   const std::string& b,
                    const EchoStringsCallback& callback) override {
     CHECK(false) << "Not implemented.";
   }
 
   void EchoMessagePipeHandle(
       ScopedMessagePipeHandle a,
       const EchoMessagePipeHandleCallback& callback) override {
     CHECK(false) << "Not implemented.";
   }
 
@@ skipping 230 matching lines @@
   regex.clear();
 #endif  // OS_WIN
   EXPECT_DEATH_IF_SUPPORTED(server_impl.DeleteCallback(), regex.c_str());
 #endif  // (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)) &&
         // !defined(OS_ANDROID)
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace mojo