Service Manager: Remove ServiceContext* arg from Service::OnStart()

services/image_decoder/image_decoder_service.cc

Index: services/image_decoder/image_decoder_service.cc
diff --git a/services/image_decoder/image_decoder_service.cc b/services/image_decoder/image_decoder_service.cc
index ddfbf93d3467119e941261c6e18e04cf752a0ce4..5295e25299989e39804b2b4676759903a7c9ff57 100644
--- a/services/image_decoder/image_decoder_service.cc
+++ b/services/image_decoder/image_decoder_service.cc
@@ -39,10 +39,10 @@ std::unique_ptr<service_manager::Service> ImageDecoderService::Create() {
   return base::MakeUnique<ImageDecoderService>();
 }
 
-void ImageDecoderService::OnStart(service_manager::ServiceContext* context) {
+void ImageDecoderService::OnStart() {
   ref_factory_.reset(new service_manager::ServiceContextRefFactory(
       base::Bind(&service_manager::ServiceContext::RequestQuit,
-                 base::Unretained(context))));
+                 base::Unretained(context()))));
 }
 
 bool ImageDecoderService::OnConnect(