[Background Sync] Add renderer code to interface between JS API and back-end service

content/child/blink_platform_impl.cc

Index: content/child/blink_platform_impl.cc
diff --git a/content/child/blink_platform_impl.cc b/content/child/blink_platform_impl.cc
index cdac32f76608e2a203e73d986b387f14d81274d7..d681df921e109ae802912d697d460823febf2e02 100644
--- a/content/child/blink_platform_impl.cc
+++ b/content/child/blink_platform_impl.cc
@@ -31,6 +31,8 @@
 #include "components/scheduler/child/webthread_impl_for_worker_scheduler.h"
 #include "content/app/resources/grit/content_resources.h"
 #include "content/app/strings/grit/content_strings.h"
+#include "content/child/background_sync/background_sync_provider.h"
+#include "content/child/background_sync/background_sync_provider_thread_proxy.h"
 #include "content/child/bluetooth/web_bluetooth_impl.h"
 #include "content/child/child_thread_impl.h"
 #include "content/child/content_child_helpers.h"
@@ -451,6 +453,8 @@ void BlinkPlatformImpl::InternalInit() {
     push_dispatcher_ = ChildThreadImpl::current()->push_dispatcher();
     permission_client_.reset(new PermissionDispatcher(
         ChildThreadImpl::current()->service_registry()));
+    sync_provider_.reset(new BackgroundSyncProvider(
+        ChildThreadImpl::current()->service_registry()));
   }
 
   if (main_thread_task_runner_.get()) {
@@ -1177,6 +1181,17 @@ blink::WebPermissionClient* BlinkPlatformImpl::permissionClient() {
       main_thread_task_runner_.get(), permission_client_.get());
 }
 
+blink::WebSyncProvider* BlinkPlatformImpl::backgroundSyncProvider() {
+  if (!sync_provider_.get())
+    return nullptr;
+
+  if (IsMainThread())
+    return sync_provider_.get();
+
+  return BackgroundSyncProviderThreadProxy::GetThreadInstance(
+      main_thread_task_runner_.get(), sync_provider_.get());
+}
+
 WebThemeEngine* BlinkPlatformImpl::themeEngine() {
   return &native_theme_engine_;
 }