[Sync] Replace uses of ObserverListThreadSafe with WeakHandles

chrome/browser/sync/notifier/non_blocking_invalidation_notifier.cc

Index: chrome/browser/sync/notifier/non_blocking_invalidation_notifier.cc
diff --git a/chrome/browser/sync/notifier/non_blocking_invalidation_notifier.cc b/chrome/browser/sync/notifier/non_blocking_invalidation_notifier.cc
index 40a1f91c9eb8edc6912e93d753e0b25eaa80f6a9..674c223d48824f76c21181da1c964f05a43e1217 100644
--- a/chrome/browser/sync/notifier/non_blocking_invalidation_notifier.cc
+++ b/chrome/browser/sync/notifier/non_blocking_invalidation_notifier.cc
@@ -7,10 +7,8 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
-#include "base/observer_list_threadsafe.h"
 #include "base/threading/thread.h"
 #include "chrome/browser/sync/notifier/invalidation_notifier.h"
-#include "chrome/browser/sync/notifier/sync_notifier_observer.h"
 
 namespace sync_notifier {
 
@@ -18,12 +16,11 @@ class NonBlockingInvalidationNotifier::Core
     : public base::RefCountedThreadSafe<NonBlockingInvalidationNotifier::Core>,
       public SyncNotifierObserver {
  public:
-  // Called on parent thread.
-  Core();
-
-  // Called on parent thread.
-  void AddObserver(SyncNotifierObserver* observer);
-  void RemoveObserver(SyncNotifierObserver* observer);
+  // Called on parent thread.  |delegate_observer| should be
+  // initialized.
+  explicit Core(
+      const browser_sync::WeakHandle<SyncNotifierObserver>&
+          delegate_observer);
 
   // Helpers called on I/O thread.
   void Initialize(
@@ -50,14 +47,19 @@ class NonBlockingInvalidationNotifier::Core
   // Called on parent or I/O thread.
   ~Core();
 
+  // The variables below should be used only on the I/O thread.
+  const browser_sync::WeakHandle<SyncNotifierObserver> delegate_observer_;
   scoped_ptr<InvalidationNotifier> invalidation_notifier_;
   scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
-  scoped_refptr<ObserverListThreadSafe<SyncNotifierObserver> > observers_;
+
   DISALLOW_COPY_AND_ASSIGN(Core);
 };
 
-NonBlockingInvalidationNotifier::Core::Core()
-    : observers_(new ObserverListThreadSafe<SyncNotifierObserver>()) {
+NonBlockingInvalidationNotifier::Core::Core(
+    const browser_sync::WeakHandle<SyncNotifierObserver>&
+        delegate_observer)
+    : delegate_observer_(delegate_observer) {
+  DCHECK(delegate_observer_.IsInitialized());
 }
 
 NonBlockingInvalidationNotifier::Core::~Core() {
@@ -92,16 +94,6 @@ void NonBlockingInvalidationNotifier::Core::Teardown() {
   io_message_loop_proxy_ = NULL;
 }
 
-void NonBlockingInvalidationNotifier::Core::AddObserver(
-    SyncNotifierObserver* observer) {
-  observers_->AddObserver(observer);
-}
-
-void NonBlockingInvalidationNotifier::Core::RemoveObserver(
-    SyncNotifierObserver* observer) {
-  observers_->RemoveObserver(observer);
-}
-
 void NonBlockingInvalidationNotifier::Core::SetUniqueId(
     const std::string& unique_id) {
   DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
@@ -129,21 +121,24 @@ void NonBlockingInvalidationNotifier::Core::UpdateEnabledTypes(
 void NonBlockingInvalidationNotifier::Core::OnIncomingNotification(
         const syncable::ModelTypePayloadMap& type_payloads) {
   DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-  observers_->Notify(&SyncNotifierObserver::OnIncomingNotification,
-                     type_payloads);
+  delegate_observer_.Call(FROM_HERE,
+                          &SyncNotifierObserver::OnIncomingNotification,
+                          type_payloads);
 }
 
 void NonBlockingInvalidationNotifier::Core::OnNotificationStateChange(
         bool notifications_enabled) {
   DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-  observers_->Notify(&SyncNotifierObserver::OnNotificationStateChange,
-                     notifications_enabled);
+  delegate_observer_.Call(FROM_HERE,
+                          &SyncNotifierObserver::OnNotificationStateChange,
+                          notifications_enabled);
 }
 
 void NonBlockingInvalidationNotifier::Core::StoreState(
     const std::string& state) {
   DCHECK(io_message_loop_proxy_->BelongsToCurrentThread());
-  observers_->Notify(&SyncNotifierObserver::StoreState, state);
+  delegate_observer_.Call(FROM_HERE,
+                          &SyncNotifierObserver::StoreState, state);
 }
 
 NonBlockingInvalidationNotifier::NonBlockingInvalidationNotifier(
@@ -152,7 +147,10 @@ NonBlockingInvalidationNotifier::NonBlockingInvalidationNotifier(
     const browser_sync::WeakHandle<InvalidationVersionTracker>&
         invalidation_version_tracker,
     const std::string& client_info)
-        : core_(new Core),
+        : weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
+          core_(
+              new Core(browser_sync::MakeWeakHandle(
+                  weak_ptr_factory_.GetWeakPtr()))),
           parent_message_loop_proxy_(
               base::MessageLoopProxy::current()),
           io_message_loop_proxy_(notifier_options.request_context_getter->
@@ -183,13 +181,13 @@ NonBlockingInvalidationNotifier::~NonBlockingInvalidationNotifier() {
 void NonBlockingInvalidationNotifier::AddObserver(
     SyncNotifierObserver* observer) {
   DCHECK(parent_message_loop_proxy_->BelongsToCurrentThread());
-  core_->AddObserver(observer);
+  observers_.AddObserver(observer);
 }
 
 void NonBlockingInvalidationNotifier::RemoveObserver(
     SyncNotifierObserver* observer) {
   DCHECK(parent_message_loop_proxy_->BelongsToCurrentThread());
-  core_->RemoveObserver(observer);
+  observers_.RemoveObserver(observer);
 }
 
 void NonBlockingInvalidationNotifier::SetUniqueId(
@@ -242,4 +240,25 @@ void NonBlockingInvalidationNotifier::SendNotification(
   // need to forward on the call.
 }
 
+void NonBlockingInvalidationNotifier::OnIncomingNotification(
+        const syncable::ModelTypePayloadMap& type_payloads) {
+  DCHECK(parent_message_loop_proxy_->BelongsToCurrentThread());
+  FOR_EACH_OBSERVER(SyncNotifierObserver, observers_,
+                    OnIncomingNotification(type_payloads));
+}
+
+void NonBlockingInvalidationNotifier::OnNotificationStateChange(
+        bool notifications_enabled) {
+  DCHECK(parent_message_loop_proxy_->BelongsToCurrentThread());
+  FOR_EACH_OBSERVER(SyncNotifierObserver, observers_,
+                    OnNotificationStateChange(notifications_enabled));
+}
+
+void NonBlockingInvalidationNotifier::StoreState(
+    const std::string& state) {
+  DCHECK(parent_message_loop_proxy_->BelongsToCurrentThread());
+  FOR_EACH_OBSERVER(SyncNotifierObserver, observers_,
+                    StoreState(state));
+}
+
 }  // namespace sync_notifier