Make MessageHandler be a pure virtual interface.

Bug: webrtc:11908
Change-Id: I35d3c4005d970082bff8c5ff24186aab54205c37
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/185340
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32194}

audio/null_audio_poller.cc

@@ -31,8 +31,7 @@ constexpr size_t kNumSamples = kSamplesPerSecond / 100;  // 10ms of samples
 }  // namespace
 
 NullAudioPoller::NullAudioPoller(AudioTransport* audio_transport)
-    : MessageHandler(false),
-      audio_transport_(audio_transport),
+    : audio_transport_(audio_transport),
       reschedule_at_(rtc::TimeMillis() + kPollDelayMs) {
   RTC_DCHECK(audio_transport);
   OnMessage(nullptr);  // Start the poll loop.

examples/peerconnection/client/peer_connection_client.cc

@@ -43,11 +43,7 @@ rtc::AsyncSocket* CreateClientSocket(int family) {
 }  // namespace
 
 PeerConnectionClient::PeerConnectionClient()
-    : MessageHandler(false),
-      callback_(NULL),
-      resolver_(NULL),
-      state_(NOT_CONNECTED),
-      my_id_(-1) {}
+    : callback_(NULL), resolver_(NULL), state_(NOT_CONNECTED), my_id_(-1) {}
 
 PeerConnectionClient::~PeerConnectionClient() {
   rtc::Thread::Current()->Clear(this);

p2p/base/stun_request.cc

@@ -174,8 +174,7 @@ bool StunRequestManager::CheckResponse(const char* data, size_t size) {
 }
 
 StunRequest::StunRequest()
-    : rtc::MessageHandler(false),
-      count_(0),
+    : count_(0),
       timeout_(false),
       manager_(0),
       msg_(new StunMessage()),
@@ -184,12 +183,7 @@ StunRequest::StunRequest()
 }
 
 StunRequest::StunRequest(StunMessage* request)
-    : rtc::MessageHandler(false),
-      count_(0),
-      timeout_(false),
-      manager_(0),
-      msg_(request),
-      tstamp_(0) {
+    : count_(0), timeout_(false), manager_(0), msg_(request), tstamp_(0) {
   msg_->SetTransactionID(rtc::CreateRandomString(kStunTransactionIdLength));
 }
 

pc/peer_connection.cc

@@ -1026,8 +1026,7 @@ void ExtractSharedMediaSessionOptions(
 PeerConnection::PeerConnection(PeerConnectionFactory* factory,
                                std::unique_ptr<RtcEventLog> event_log,
                                std::unique_ptr<Call> call)
-    : MessageHandler(false),
-      factory_(factory),
+    : factory_(factory),
       event_log_(std::move(event_log)),
       event_log_ptr_(event_log_.get()),
       operations_chain_(rtc::OperationsChain::Create()),

pc/remote_audio_source.cc

@@ -50,8 +50,7 @@ class RemoteAudioSource::AudioDataProxy : public AudioSinkInterface {
 };
 
 RemoteAudioSource::RemoteAudioSource(rtc::Thread* worker_thread)
-    : MessageHandler(false),
-      main_thread_(rtc::Thread::Current()),
+    : main_thread_(rtc::Thread::Current()),
       worker_thread_(worker_thread),
       state_(MediaSourceInterface::kLive) {
   RTC_DCHECK(main_thread_);

pc/webrtc_session_description_factory.cc

@@ -130,8 +130,7 @@ WebRtcSessionDescriptionFactory::WebRtcSessionDescriptionFactory(
     std::unique_ptr<rtc::RTCCertificateGeneratorInterface> cert_generator,
     const rtc::scoped_refptr<rtc::RTCCertificate>& certificate,
     UniqueRandomIdGenerator* ssrc_generator)
-    : MessageHandler(false),
-      signaling_thread_(signaling_thread),
+    : signaling_thread_(signaling_thread),
       session_desc_factory_(channel_manager,
                             &transport_desc_factory_,
                             ssrc_generator),

rtc_base/message_handler.cc

@@ -14,14 +14,7 @@
 
 namespace rtc {
 
-MessageHandler::MessageHandler(bool auto_cleanup) {
-  RTC_DCHECK(!auto_cleanup) << "Use MessageHandlerAutoCleanup";
-}
-
-MessageHandler::~MessageHandler() {}
-
-MessageHandlerAutoCleanup::MessageHandlerAutoCleanup()
-    : MessageHandler(false) {}
+MessageHandlerAutoCleanup::MessageHandlerAutoCleanup() {}
 
 MessageHandlerAutoCleanup::~MessageHandlerAutoCleanup() {
   // Note that even though this clears currently pending messages for the

rtc_base/message_handler.h

@@ -21,29 +21,18 @@ namespace rtc {
 
 struct Message;
 
-// MessageQueue/Thread Messages get dispatched to a MessageHandler via the
-// |OnMessage()| callback method.
-//
-// Note: Besides being an interface, the class can perform automatic cleanup
-// in the destructor.
-// TODO(bugs.webrtc.org/11908): The |auto_cleanup| parameter and associated
-// logic is a temporary step while changing the MessageHandler class to be
-// a pure virtual interface. The automatic cleanup step involves a number of
-// complex operations and as part of this interface, can easily go by unnoticed
-// and bundled into situations where it's not needed.
+// MessageQueue/Thread Messages get dispatched via the MessageHandler interface.
 class RTC_EXPORT MessageHandler {
  public:
-  virtual ~MessageHandler();
+  virtual ~MessageHandler() {}
   virtual void OnMessage(Message* msg) = 0;
-
- protected:
-  // TODO(bugs.webrtc.org/11908): Remove this ctor.
-  explicit MessageHandler(bool auto_cleanup);
-
- private:
-  RTC_DISALLOW_COPY_AND_ASSIGN(MessageHandler);
 };
 
+// Warning: Provided for backwards compatibility.
+//
+// This class performs expensive cleanup in the dtor that will affect all
+// instances of Thread (and their pending message queues) and will block the
+// current thread as well as all other threads.
 class RTC_EXPORT MessageHandlerAutoCleanup : public MessageHandler {
  public:
   ~MessageHandlerAutoCleanup() override;

rtc_base/thread.cc

@@ -74,7 +74,7 @@ const int kSlowDispatchLoggingThreshold = 50;  // 50 ms
 
 class MessageHandlerWithTask final : public MessageHandler {
  public:
-  MessageHandlerWithTask() : MessageHandler(false) {}
+  MessageHandlerWithTask() {}
 
   void OnMessage(Message* msg) override {
     static_cast<rtc_thread_internal::MessageLikeTask*>(msg->pdata)->Run();
@@ -961,7 +961,7 @@ void Thread::InvokeInternal(const Location& posted_from,
   class FunctorMessageHandler : public MessageHandler {
    public:
     explicit FunctorMessageHandler(rtc::FunctionView<void()> functor)
-        : MessageHandler(false), functor_(functor) {}
+        : functor_(functor) {}
     void OnMessage(Message* msg) override { functor_(); }
 
    private:

rtc_base/thread.h

@@ -534,7 +534,7 @@ class RTC_LOCKABLE RTC_EXPORT Thread : public webrtc::TaskQueueBase {
  private:
   class QueuedTaskHandler final : public MessageHandler {
    public:
-    QueuedTaskHandler() : MessageHandler(false) {}
+    QueuedTaskHandler() {}
     void OnMessage(Message* msg) override;
   };
 

sdk/android/src/jni/pc/peer_connection_factory.cc

@@ -82,9 +82,7 @@ void PostJavaCallback(JNIEnv* env,
     JavaAsyncCallback(JNIEnv* env,
                       const JavaRef<jobject>& j_object,
                       JavaMethodPointer java_method_pointer)
-        : rtc::MessageHandler(false),
-          j_object_(env, j_object),
-          java_method_pointer_(java_method_pointer) {}
+        : j_object_(env, j_object), java_method_pointer_(java_method_pointer) {}
 
     void OnMessage(rtc::Message*) override {
       java_method_pointer_(AttachCurrentThreadIfNeeded(), j_object_);

sdk/objc/native/src/audio/audio_device_ios.mm

@@ -101,8 +101,7 @@ static void LogDeviceInfo() {
 #endif  // !defined(NDEBUG)
 
 AudioDeviceIOS::AudioDeviceIOS()
-    : MessageHandler(false),
-      audio_device_buffer_(nullptr),
+    : audio_device_buffer_(nullptr),
       audio_unit_(nullptr),
       recording_(0),
       playing_(0),