Change BackgroundSyncContextImpl to use StrongBindingSet.

content/browser/background_sync/background_sync_context_impl.h

Index: content/browser/background_sync/background_sync_context_impl.h
diff --git a/content/browser/background_sync/background_sync_context_impl.h b/content/browser/background_sync/background_sync_context_impl.h
index c5a91039ec4d615aff756345fc8ce2bc70a48653..5787d70fef23d3708fd7c186ccad22b1d44baffa 100644
--- a/content/browser/background_sync/background_sync_context_impl.h
+++ b/content/browser/background_sync/background_sync_context_impl.h
@@ -5,18 +5,18 @@
 #ifndef CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_CONTEXT_IMPL_H_
 #define CONTENT_BROWSER_BACKGROUND_SYNC_BACKGROUND_SYNC_CONTEXT_IMPL_H_
 
-#include <set>
-
+#include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "content/browser/background_sync/background_sync_service_impl.h"
 #include "content/common/background_sync_service.mojom.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/background_sync_context.h"
+#include "mojo/common/strong_binding_set.h"
 
 namespace content {
 
 class BackgroundSyncManager;
-class BackgroundSyncServiceImpl;
 class ServiceWorkerContextWrapper;
 
 // Implements the BackgroundSyncContext. One instance of this exists per
@@ -38,10 +38,6 @@ class CONTENT_EXPORT BackgroundSyncContextImpl : public BackgroundSyncContext {
   // thread.
   void CreateService(mojo::InterfaceRequest<BackgroundSyncService> request);
 
-  // Called by BackgroundSyncServiceImpl objects so that they can
-  // be deleted. Call on the IO thread.
-  void ServiceHadConnectionError(BackgroundSyncServiceImpl* service);
-
   // Call on the IO thread.
   BackgroundSyncManager* background_sync_manager() const override;
 
@@ -65,7 +61,7 @@ class CONTENT_EXPORT BackgroundSyncContextImpl : public BackgroundSyncContext {
   // The services are owned by this. They're either deleted
   // during ShutdownOnIO or when the channel is closed via
   // ServiceHadConnectionError. Only accessed on the IO thread.
-  std::set<BackgroundSyncServiceImpl*> services_;
+  mojo::StrongBindingSet<BackgroundSyncServiceImpl> services_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundSyncContextImpl);
 };