Use mojo to connect to BackgroundSyncManager object

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 c8f41688a6fb8017f9075e160af300c0d5673640..ed82c3b17cea393c5bfca2540e5c6ab578189c8c 100644
--- a/content/child/blink_platform_impl.cc
+++ b/content/child/blink_platform_impl.cc
@@ -38,7 +38,6 @@
 #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/child_thread_impl.h"
 #include "content/child/content_child_helpers.h"
 #include "content/child/geofencing/web_geofencing_provider_impl.h"
@@ -459,8 +458,9 @@ 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()));
+    main_thread_sync_provider_.reset(
+        BackgroundSyncProvider::GetOrCreateThreadSpecificInstance(
+            main_thread_task_runner_.get()));
   }
 }
 
@@ -1213,14 +1213,8 @@ blink::WebPermissionClient* BlinkPlatformImpl::permissionClient() {
 }
 
 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());
+  return BackgroundSyncProvider::GetOrCreateThreadSpecificInstance(
+      main_thread_task_runner_.get());
 }
 
 WebThemeEngine* BlinkPlatformImpl::themeEngine() {