PaymentApp: Add PaymentAppProvider class.

content/browser/payments/payment_app_provider_impl.cc

+// Copyright 2017 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 "content/browser/payments/payment_app_provider_impl.h"
+
+#include "content/browser/payments/payment_app_context_impl.h"
+#include "content/browser/storage_partition_impl.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+namespace {
+
+void DidGetAllManifestsOnIO(
+    const PaymentAppProvider::GetAllManifestsCallback& callback,
+    PaymentAppProvider::Manifests manifests) {
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(callback, base::Passed(std::move(manifests))));
+}
+
+void GetAllManifestsOnIO(
+    const scoped_refptr<PaymentAppContextImpl>& payment_app_context,
+    const PaymentAppProvider::GetAllManifestsCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  payment_app_context->payment_app_database()->ReadAllManifests(
+      base::Bind(&DidGetAllManifestsOnIO, callback));
+}
+
+}  // namespace
+
+// static
+PaymentAppProvider* PaymentAppProvider::GetInstance() {
+  return PaymentAppProviderImpl::GetInstance();
+}
+

[please use gerrit instead, 2017/01/04 16:55:43]

Also needs "// static" comment.

[zino, 2017/01/04 17:29:59]

Done.

+PaymentAppProviderImpl* PaymentAppProviderImpl::GetInstance() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  return base::Singleton<PaymentAppProviderImpl>::get();
+}
+
+PaymentAppProviderImpl::PaymentAppProviderImpl() {}
+
+PaymentAppProviderImpl::~PaymentAppProviderImpl() {}
+
+void PaymentAppProviderImpl::GetAllManifests(

[please use gerrit instead, 2017/01/04 16:55:43]

Please keep all methods in .cc in the same order as in the corresponding .h
file.

[zino, 2017/01/04 17:29:59]

Done.

+    BrowserContext* browser_context,
+    const GetAllManifestsCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  StoragePartitionImpl* partition = static_cast<StoragePartitionImpl*>(
+      BrowserContext::GetDefaultStoragePartition(browser_context));
+  scoped_refptr<PaymentAppContextImpl> payment_app_context =
+      partition->GetPaymentAppContext();
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&GetAllManifestsOnIO, payment_app_context, callback));
+}
+
+}  // namespace content