Revert of Deletes mojo::Callback

extensions/browser/mojo/stash_backend.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 "extensions/browser/mojo/stash_backend.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 #include "mojo/public/cpp/system/watcher.h"
 
 namespace extensions {
 namespace {
 
 // An implementation of StashService that forwards calls to a StashBackend.
 class StashServiceImpl : public StashService {
  public:
   StashServiceImpl(mojo::InterfaceRequest<StashService> request,
                    base::WeakPtr<StashBackend> backend);
   ~StashServiceImpl() override;
 
   // StashService overrides.
   void AddToStash(mojo::Array<StashedObjectPtr> stash) override;
-  void RetrieveStash(const RetrieveStashCallback& callback) override;
+  void RetrieveStash(
+      const mojo::Callback<void(mojo::Array<StashedObjectPtr> stash)>& callback)
+      override;
 
  private:
   mojo::StrongBinding<StashService> binding_;
   base::WeakPtr<StashBackend> backend_;
 
   DISALLOW_COPY_AND_ASSIGN(StashServiceImpl);
 };
 
 StashServiceImpl::StashServiceImpl(mojo::InterfaceRequest<StashService> request,
                                    base::WeakPtr<StashBackend> backend)
     : binding_(this, std::move(request)), backend_(backend) {}
 
 StashServiceImpl::~StashServiceImpl() {
 }
 
 void StashServiceImpl::AddToStash(
     mojo::Array<StashedObjectPtr> stashed_objects) {
   if (!backend_)
     return;
   backend_->AddToStash(std::move(stashed_objects));
 }
 
-void StashServiceImpl::RetrieveStash(const RetrieveStashCallback& callback) {
+void StashServiceImpl::RetrieveStash(
+    const mojo::Callback<void(mojo::Array<StashedObjectPtr>)>& callback) {
   if (!backend_) {
     callback.Run(mojo::Array<StashedObjectPtr>());
     return;
   }
   callback.Run(backend_->RetrieveStash());
 }
 
 }  // namespace
 
 // A stash entry for a stashed object. This handles notifications if a handle
@@ skipping 99 matching lines @@
   waiters_.clear();
 }
 
 void StashBackend::StashEntry::OnHandleReady(MojoResult result) {
   if (result != MOJO_RESULT_OK)
     return;
   on_handle_readable_.Run();
 }
 
 }  // namespace extensions