From e4099c06837e4b955a23ff815fa6e318af7dc133 Mon Sep 17 00:00:00 2001
From: alwu <alwu@mozilla.com>
Date: Tue, 29 Oct 2019 23:46:36 +0000
Subject: [PATCH] Bug 1591620 - part1 : make 'MediaControlKeysEventListener' as
 a pure interface. r=chunmin

If the web extention also needs to implement its listener, they would definitely not need the current implementation in `KeyPressed()` for controlling media controller. Therefore, we should make `MediaControlKeysEventListener` as a pure interface and let inherited class to define their own `KeyPressed()`.

Differential Revision: https://phabricator.services.mozilla.com/D50686

--HG--
extra : moz-landing-system : lando
---
 .../mediacontrol/MediaControlKeysEvent.cpp    |  3 +--
 .../mediacontrol/MediaControlKeysEvent.h      | 19 ++++++++++++++-----
 .../mediacontrol/MediaControlKeysManager.cpp  |  2 +-
 .../tests/gtest/TestMediaKeysEvent.cpp        |  2 +-
 4 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/dom/media/mediacontrol/MediaControlKeysEvent.cpp b/dom/media/mediacontrol/MediaControlKeysEvent.cpp
index f877b515418a..fb1f8f46a0fe 100644
--- a/dom/media/mediacontrol/MediaControlKeysEvent.cpp
+++ b/dom/media/mediacontrol/MediaControlKeysEvent.cpp
@@ -42,8 +42,7 @@ static const char* ToMediaControlKeysEventStr(MediaControlKeysEvent aKeyEvent) {
              ToMediaControlKeysEventStr(key), ##__VA_ARGS__));    \
   }
 
-void MediaControlKeysEventListener::OnKeyPressed(
-    MediaControlKeysEvent aKeyEvent) {
+void MediaControlKeysHandler::OnKeyPressed(MediaControlKeysEvent aKeyEvent) {
   LOG_KEY("OnKeyPressed '%s'", aKeyEvent);
   switch (aKeyEvent) {
     case MediaControlKeysEvent::ePlayPause: {
diff --git a/dom/media/mediacontrol/MediaControlKeysEvent.h b/dom/media/mediacontrol/MediaControlKeysEvent.h
index 38354a215cdc..1763cf1f901a 100644
--- a/dom/media/mediacontrol/MediaControlKeysEvent.h
+++ b/dom/media/mediacontrol/MediaControlKeysEvent.h
@@ -14,22 +14,31 @@ namespace dom {
 enum class MediaControlKeysEvent { ePlayPause, ePrev, eNext, eNone };
 
 /**
- * MediaControlKeysEventListener is used to monitor MediaControlKeysEvent, we
- * can add it onto the MediaControlKeysEventSource, and then everytime when
- * the media key events occur, `OnKeyPressed` will be called so that we can do
- * related handling.
+ * MediaControlKeysEventListener is a pure interface, which is used to monitor
+ * MediaControlKeysEvent, we can add it onto the MediaControlKeysEventSource,
+ * and then everytime when the media key events occur, `OnKeyPressed` will be
+ * called so that we can do related handling.
  */
 class MediaControlKeysEventListener {
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaControlKeysEventListener);
   MediaControlKeysEventListener() = default;
 
-  virtual void OnKeyPressed(MediaControlKeysEvent aKeyEvent);
+  virtual void OnKeyPressed(MediaControlKeysEvent aKeyEvent) = 0;
 
  protected:
   virtual ~MediaControlKeysEventListener() = default;
 };
 
+/**
+ * MediaControlKeysHandler is used to operate media controller by corresponding
+ * received media control key events.
+ */
+class MediaControlKeysHandler final : public MediaControlKeysEventListener {
+ public:
+  void OnKeyPressed(MediaControlKeysEvent aKeyEvent) override;
+};
+
 /**
  * MediaControlKeysEventSource is a base class which is used to implement
  * transporting media control keys event to all its listeners when media keys
diff --git a/dom/media/mediacontrol/MediaControlKeysManager.cpp b/dom/media/mediacontrol/MediaControlKeysManager.cpp
index 19aec02709f1..f9c911c7f1e1 100644
--- a/dom/media/mediacontrol/MediaControlKeysManager.cpp
+++ b/dom/media/mediacontrol/MediaControlKeysManager.cpp
@@ -36,7 +36,7 @@ void MediaControlKeysManager::StartMonitoringControlKeys() {
   }
   CreateEventSource();
   if (mEventSource) {
-    mEventSource->AddListener(new MediaControlKeysEventListener());
+    mEventSource->AddListener(new MediaControlKeysHandler());
   }
 }
 
diff --git a/dom/media/mediacontrol/tests/gtest/TestMediaKeysEvent.cpp b/dom/media/mediacontrol/tests/gtest/TestMediaKeysEvent.cpp
index b0682224978f..1c9e1c16ea5c 100644
--- a/dom/media/mediacontrol/tests/gtest/TestMediaKeysEvent.cpp
+++ b/dom/media/mediacontrol/tests/gtest/TestMediaKeysEvent.cpp
@@ -14,7 +14,7 @@ TEST(MediaControlKeysEvent, TestAddOrRemoveListener)
   ASSERT_TRUE(source->GetListenersNum() == 0);
 
   RefPtr<MediaControlKeysEventListener> listener =
-      new MediaControlKeysEventListener();
+      new MediaControlKeysHandler();
 
   source->AddListener(listener);
   ASSERT_TRUE(source->GetListenersNum() == 1);