[mojo-bindings] Use Watcher API for JS bindings

mojo/edk/js/support.cc

 // 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.
 
 #include "mojo/edk/js/support.h"
 
 #include "base/bind.h"
 #include "gin/arguments.h"
 #include "gin/converter.h"
 #include "gin/function_template.h"
 #include "gin/object_template_builder.h"
 #include "gin/per_isolate_data.h"
 #include "gin/public/wrapper_info.h"
 #include "gin/wrappable.h"
 #include "mojo/edk/js/handle.h"
 #include "mojo/edk/js/waiting_callback.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace mojo {
 namespace edk {
 namespace js {
 
 namespace {
 
 WaitingCallback* AsyncWait(const gin::Arguments& args,
                            gin::Handle<HandleWrapper> handle,
                            MojoHandleSignals signals,
                            v8::Handle<v8::Function> callback) {
-  return WaitingCallback::Create(args.isolate(), callback, handle, signals)
-             .get();
+  return WaitingCallback::Create(
+      args.isolate(), callback, handle, signals, true /* one_shot */).get();
 }
 
 void CancelWait(WaitingCallback* waiting_callback) {
   waiting_callback->Cancel();
 }
 
+WaitingCallback* Watch(const gin::Arguments& args,
+                       gin::Handle<HandleWrapper> handle,
+                       MojoHandleSignals signals,
+                       v8::Handle<v8::Function> callback) {
+  return WaitingCallback::Create(
+      args.isolate(), callback, handle, signals, false /* one_shot */).get();
+}
+
+void CancelWatch(WaitingCallback* waiting_callback) {
+  waiting_callback->Cancel();
+}
+
 gin::WrapperInfo g_wrapper_info = { gin::kEmbedderNativeGin };
 
 }  // namespace
 
 const char Support::kModuleName[] = "mojo/public/js/support";
 
 v8::Local<v8::Value> Support::GetModule(v8::Isolate* isolate) {
   gin::PerIsolateData* data = gin::PerIsolateData::From(isolate);
   v8::Local<v8::ObjectTemplate> templ = data->GetObjectTemplate(
       &g_wrapper_info);
 
   if (templ.IsEmpty()) {
     templ = gin::ObjectTemplateBuilder(isolate)
+                // TODO(rockot): Remove asyncWait and cancelWait.
                 .SetMethod("asyncWait", AsyncWait)
                 .SetMethod("cancelWait", CancelWait)
+                .SetMethod("watch", Watch)
+                .SetMethod("cancelWatch", CancelWatch)
                 .Build();
 
     data->SetObjectTemplate(&g_wrapper_info, templ);
   }
 
   return templ->NewInstance();
 }
 
 }  // namespace js
 }  // namespace edk
 }  // namespace mojo