Bug 1604962 - use NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING to support refcounting for abstrach classes. r=chunmin

Inheriting from `nsISupports` is too complicated if we just want to support refcounting. Instead, we can use `NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING` to declare `Add/RemoveRef()` as pure virtual functions in order to create ref-counted abstract classes.

Differential Revision: https://phabricator.services.mozilla.com/D57714

--HG--
extra : moz-landing-system : lando

dom/media/mediacontrol/MediaControlKeysEvent.cpp

@@ -25,8 +25,6 @@ namespace dom {
           ("MediaControlKeysHandler=%p, " msg, this, \
            ToMediaControlKeysEventStr(key), ##__VA_ARGS__));
 
-NS_IMPL_ISUPPORTS0(MediaControlKeysHandler)
-
 void MediaControlKeysHandler::OnKeyPressed(MediaControlKeysEvent aKeyEvent) {
   LOG_KEY("OnKeyPressed '%s'", aKeyEvent);
 
@@ -71,8 +69,6 @@ void MediaControlKeysHandler::OnKeyPressed(MediaControlKeysEvent aKeyEvent) {
   }
 }
 
-NS_IMPL_ISUPPORTS0(MediaControlKeysEventSource)
-
 void MediaControlKeysEventSource::AddListener(
     MediaControlKeysEventListener* aListener) {
   MOZ_ASSERT(aListener);

dom/media/mediacontrol/MediaControlKeysEvent.h

@@ -36,8 +36,9 @@ enum class MediaControlKeysEvent : uint32_t {
  * and then everytime when the media key events occur, `OnKeyPressed` will be
  * called so that we can do related handling.
  */
-class MediaControlKeysEventListener : public nsISupports {
+class MediaControlKeysEventListener {
  public:
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
   MediaControlKeysEventListener() = default;
 
   virtual void OnKeyPressed(MediaControlKeysEvent aKeyEvent) = 0;
@@ -52,8 +53,7 @@ class MediaControlKeysEventListener : public nsISupports {
  */
 class MediaControlKeysHandler final : public MediaControlKeysEventListener {
  public:
-  NS_DECL_ISUPPORTS
-
+  NS_INLINE_DECL_REFCOUNTING(MediaControlKeysHandler, override)
   void OnKeyPressed(MediaControlKeysEvent aKeyEvent) override;
 
  private:
@@ -61,14 +61,13 @@ class MediaControlKeysHandler final : public MediaControlKeysEventListener {
 };
 
 /**
- * MediaControlKeysEventSource is a base class which is used to implement
+ * MediaControlKeysEventSource is an abstract class which is used to implement
  * transporting media control keys event to all its listeners when media keys
  * event happens.
  */
-class MediaControlKeysEventSource : public nsISupports {
+class MediaControlKeysEventSource {
  public:
-  NS_DECL_ISUPPORTS
-
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
   MediaControlKeysEventSource() = default;
 
   virtual void AddListener(MediaControlKeysEventListener* aListener);

dom/media/mediacontrol/MediaControlKeysManager.cpp

@@ -20,9 +20,6 @@
 namespace mozilla {
 namespace dom {
 
-NS_IMPL_ISUPPORTS_INHERITED0(MediaControlKeysManager,
-                             MediaControlKeysEventSource)
-
 bool MediaControlKeysManager::IsOpened() const {
   // As MediaControlKeysManager represents a platform-indenpendent event source,
   // which we can use to add other listeners to moniter media key events, we

dom/media/mediacontrol/MediaControlKeysManager.h

@@ -22,7 +22,8 @@ namespace dom {
 class MediaControlKeysManager final : public MediaControlKeysEventSource,
                                       public MediaControlKeysEventListener {
  public:
-  NS_DECL_ISUPPORTS_INHERITED
+  NS_INLINE_DECL_REFCOUNTING(MediaControlKeysManager, override)
+
   MediaControlKeysManager() = default;
 
   // MediaControlKeysEventSource methods

dom/media/mediacontrol/tests/gtest/TestMediaKeysEvent.cpp

@@ -8,8 +8,13 @@
 using namespace mozilla::dom;
 
 class MediaControlKeysEventSourceTestImpl : public MediaControlKeysEventSource {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(MediaControlKeysEventSourceTestImpl, override)
   bool Open() override { return true; }
   bool IsOpened() const override { return true; }
+
+ private:
+  ~MediaControlKeysEventSourceTestImpl() = default;
 };
 
 TEST(MediaControlKeysEvent, TestAddOrRemoveListener)

dom/media/mediacontrol/tests/gtest/TestMediaKeysEventMac.mm

@@ -19,7 +19,7 @@ static const int kSystemDefinedEventMediaKeysSubtype = 8;
 
 class MediaHardwareKeysEventListenerTest : public MediaControlKeysEventListener {
  public:
-  NS_DECL_ISUPPORTS
+  NS_INLINE_DECL_REFCOUNTING(MediaHardwareKeysEventListenerTest, override)
 
   void OnKeyPressed(MediaControlKeysEvent aKeyEvent) override {
     mReceivedEvent = mozilla::Some(aKeyEvent);
@@ -37,8 +37,6 @@ class MediaHardwareKeysEventListenerTest : public MediaControlKeysEventListener
   mozilla::Maybe<MediaControlKeysEvent> mReceivedEvent;
 };
 
-NS_IMPL_ISUPPORTS0(MediaHardwareKeysEventListenerTest)
-
 static void SendFakeEvent(RefPtr<MediaHardwareKeysEventSourceMac>& aSource, int aKeyData) {
   NSEvent* event = [NSEvent otherEventWithType:NSSystemDefined
                                       location:NSZeroPoint

widget/cocoa/MediaHardwareKeysEventSourceMac.h

@@ -17,6 +17,7 @@ namespace widget {
 class MediaHardwareKeysEventSourceMac final
     : public mozilla::dom::MediaControlKeysEventSource {
  public:
+  NS_INLINE_DECL_REFCOUNTING(MediaHardwareKeysEventSourceMac, override)
   MediaHardwareKeysEventSourceMac() = default;
 
   static CGEventRef EventTapCallback(CGEventTapProxy proxy, CGEventType type,