Remove mojo::String.

mojo/public/cpp/bindings/BUILD.gn

 # Copyright 2014 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.
 
 interfaces_bindings_gen_dir = "$root_gen_dir/mojo/public/interfaces/bindings"
 
 component("bindings") {
   sources = [
     # Normally, targets should depend on the source_sets generated by mojom
     # targets. However, the generated source_sets use portions of the bindings
@@ skipping 109 matching lines @@
     "message.h",
     "message_header_validator.h",
     "native_enum.h",
     "native_struct.h",
     "native_struct_data_view.h",
     "no_interface.h",
     "pipe_control_message_handler.h",
     "pipe_control_message_handler_delegate.h",
     "pipe_control_message_proxy.h",
     "scoped_interface_endpoint_handle.h",
-    "string.h",
     "string_data_view.h",
     "string_traits.h",
-    "string_traits_standard.h",
     "string_traits_stl.h",
     "string_traits_string16.h",
     "string_traits_string_piece.h",
     "strong_associated_binding.h",
     "strong_binding.h",
     "struct_ptr.h",
     "sync_call_restrictions.h",
     "sync_handle_registry.h",
     "sync_handle_watcher.h",
     "thread_safe_interface_ptr.h",
@@ skipping 40 matching lines @@
     ]
 
     public_deps = [
       ":bindings",
       "//third_party/WebKit/Source/wtf",
     ]
 
     public_configs = [ "//third_party/WebKit/Source:config" ]
   }
 }