Switch PermissionStatus events to an observer model.

third_party/WebKit/Source/modules/permissions/PermissionStatus.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/permissions/PermissionStatus.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/Document.h"
 #include "core/events/Event.h"
 #include "modules/EventTargetModulesNames.h"
@@ skipping 21 matching lines @@
   permissionStatus->startListening();
   return permissionStatus;
 }
 
 PermissionStatus::PermissionStatus(ExecutionContext* executionContext,
                                    MojoPermissionStatus status,
                                    MojoPermissionDescriptor descriptor)
     : ActiveScriptWrappable(this),
       SuspendableObject(executionContext),
       m_status(status),
-      m_descriptor(std::move(descriptor)) {}
+      m_descriptor(std::move(descriptor)),
+      m_binding(this) {}
 
-PermissionStatus::~PermissionStatus() {
+PermissionStatus::~PermissionStatus() {}

[mlamouri (slow - plz ping), 2016/12/19 13:37:45]

= default;

[Reilly Grant (use Gerrit), 2016/12/19 22:23:59]

Done.

+
+void PermissionStatus::dispose() {
   stopListening();
 }
 
 const AtomicString& PermissionStatus::interfaceName() const {
   return EventTargetNames::PermissionStatus;
 }
 
 ExecutionContext* PermissionStatus::getExecutionContext() const {
   return SuspendableObject::getExecutionContext();
 }
 
-void PermissionStatus::permissionChanged(MojoPermissionStatus status) {
-  if (m_status == status)
-    return;
-
-  m_status = status;
-  dispatchEvent(Event::create(EventTypeNames::change));
-
-  m_service->GetNextPermissionChange(
-      m_descriptor->Clone(), getExecutionContext()->getSecurityOrigin(),
-      m_status,
-      convertToBaseCallback(WTF::bind(&PermissionStatus::permissionChanged,
-                                      wrapWeakPersistent(this))));
-}
-
 bool PermissionStatus::hasPendingActivity() const {
-  return m_service;
+  return m_binding.is_bound();
 }
 
 void PermissionStatus::resume() {
   startListening();
 }
 
 void PermissionStatus::suspend() {
   stopListening();
 }
 
 void PermissionStatus::contextDestroyed() {
   stopListening();
 }
 
-void PermissionStatus::startListening() {
-  DCHECK(!m_service);
-  connectToPermissionService(getExecutionContext(), mojo::GetProxy(&m_service));
-  m_service->GetNextPermissionChange(
-      m_descriptor->Clone(), getExecutionContext()->getSecurityOrigin(),
-      m_status,
-      convertToBaseCallback(WTF::bind(&PermissionStatus::permissionChanged,
-                                      wrapWeakPersistent(this))));
-}
-
-void PermissionStatus::stopListening() {
-  m_service.reset();
-}
-
 String PermissionStatus::state() const {
   switch (m_status) {
     case MojoPermissionStatus::GRANTED:
       return "granted";
     case MojoPermissionStatus::DENIED:
       return "denied";
     case MojoPermissionStatus::ASK:
       return "prompt";
   }
 
   ASSERT_NOT_REACHED();
   return "denied";
 }
 
+void PermissionStatus::startListening() {
+  DCHECK(!m_binding.is_bound());
+  mojom::blink::PermissionObserverPtr observer;
+  m_binding.Bind(mojo::GetProxy(&observer));
+
+  mojom::blink::PermissionServicePtr service;
+  connectToPermissionService(getExecutionContext(), mojo::GetProxy(&service));
+  service->AddPermissionObserver(m_descriptor->Clone(),
+                                 getExecutionContext()->getSecurityOrigin(),
+                                 m_status, std::move(observer));
+}
+
+void PermissionStatus::stopListening() {
+  m_binding.Close();
+}
+
+void PermissionStatus::OnPermissionStatusChange(MojoPermissionStatus status) {
+  if (m_status != status) {

[mlamouri (slow - plz ping), 2016/12/19 13:37:45]

You should ideally prefer early returns:
```
if (m_status == status)
  return;
```

[Reilly Grant (use Gerrit), 2016/12/19 22:23:59]

Done.

+    m_status = status;
+    dispatchEvent(Event::create(EventTypeNames::change));
+  }
+}
+
 DEFINE_TRACE(PermissionStatus) {
   EventTargetWithInlineData::trace(visitor);
   SuspendableObject::trace(visitor);
 }
 
 }  // namespace blink