[media] Remove Promises from WebCodecs VideoDecoder.

Bug: 897297
Change-Id: I7bc070913b53a88a9588836c424cb9f5b6fe8283
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2231593
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#778616}

third_party/blink/renderer/modules/webcodecs/video_decoder.cc

@@ -101,51 +101,45 @@ int32_t VideoDecoder::decodeQueueSize() {
   return requested_decodes_;
 }
 
-int32_t VideoDecoder::decodeProcessingCount() {
-  return pending_decodes_.size();
-}
-
-ScriptPromise VideoDecoder::configure(const EncodedVideoConfig* config,
-                                      ExceptionState&) {
+void VideoDecoder::configure(const EncodedVideoConfig* config,
+                             ExceptionState&) {
   DVLOG(1) << __func__;
   Request* request = MakeGarbageCollected<Request>();
   request->type = Request::Type::kConfigure;
   request->config = config;
-  return EnqueueRequest(request);
+  requests_.push_back(request);
+  ProcessRequests();
 }
 
-ScriptPromise VideoDecoder::decode(const EncodedVideoChunk* chunk,
-                                   ExceptionState&) {
+void VideoDecoder::decode(const EncodedVideoChunk* chunk, ExceptionState&) {
   DVLOG(3) << __func__;
-  requested_decodes_++;
   Request* request = MakeGarbageCollected<Request>();
   request->type = Request::Type::kDecode;
   request->chunk = chunk;
-  return EnqueueRequest(request);
+  requests_.push_back(request);
+  ++requested_decodes_;
+  ProcessRequests();
 }
 
 ScriptPromise VideoDecoder::flush(ExceptionState&) {
   DVLOG(3) << __func__;
   Request* request = MakeGarbageCollected<Request>();
   request->type = Request::Type::kFlush;
-  return EnqueueRequest(request);
+  ScriptPromiseResolver* resolver =
+      MakeGarbageCollected<ScriptPromiseResolver>(script_state_);
+  request->resolver = resolver;
+  requests_.push_back(request);
+  ProcessRequests();
+  return resolver->Promise();
 }
 
-ScriptPromise VideoDecoder::reset(ExceptionState&) {
+void VideoDecoder::reset(ExceptionState&) {
   DVLOG(3) << __func__;
-  requested_resets_++;
   Request* request = MakeGarbageCollected<Request>();
   request->type = Request::Type::kReset;
-  return EnqueueRequest(request);
-}
-
-ScriptPromise VideoDecoder::EnqueueRequest(Request* request) {
-  ScriptPromiseResolver* resolver =
-      MakeGarbageCollected<ScriptPromiseResolver>(script_state_);
-  request->resolver = resolver;
   requests_.push_back(request);
+  ++requested_resets_;
   ProcessRequests();
-  return resolver->Promise();
 }
 
 void VideoDecoder::ProcessRequests() {
@@ -191,9 +185,6 @@ bool VideoDecoder::ProcessConfigureRequest(Request* request) {
     media_log_ = std::make_unique<media::NullMediaLog>();
     decoder_ = CreateVideoDecoder(media_log_.get());
     if (!decoder_) {
-      request->resolver.Release()->Reject(MakeGarbageCollected<DOMException>(
-          DOMExceptionCode::kNotSupportedError,
-          "Codec initialization failed."));
       // TODO(sandersd): This is a bit awkward because |request| is still in the
       // queue.
       HandleError();
@@ -236,11 +227,10 @@ bool VideoDecoder::ProcessDecodeRequest(Request* request) {
   DCHECK(request->chunk);
   DCHECK_GT(requested_decodes_, 0);
 
-  // TODO(sandersd): If a reset has been requested, resolve immediately.
+  // TODO(sandersd): If a reset has been requested, complete immediately.
 
   if (!decoder_) {
-    // TODO(sandersd): Add explanation (no valid configuration).
-    request->resolver.Release()->Reject();
+    // TODO(sandersd): Emit an error?
     return true;
   }
 
@@ -348,14 +338,11 @@ void VideoDecoder::OnInitializeDone(media::Status status) {
   if (!status.is_ok()) {
     // TODO(tmathmeyer) this drops the media error - should we consider logging
     // it or converting it to the DOMException type somehow?
-    pending_request_.Release()->resolver.Release()->Reject(
-        MakeGarbageCollected<DOMException>(DOMExceptionCode::kNotSupportedError,
-                                           "Codec initialization failed."));
     HandleError();
     return;
   }
 
-  pending_request_.Release()->resolver.Release()->Resolve();
+  pending_request_.Release();
   ProcessRequests();
 }
 
@@ -370,7 +357,6 @@ void VideoDecoder::OnDecodeDone(uint32_t id, media::DecodeStatus status) {
   }
 
   auto it = pending_decodes_.find(id);
-  it->value->resolver.Release()->Resolve();
   pending_decodes_.erase(it);
   ProcessRequests();
 }
@@ -394,7 +380,7 @@ void VideoDecoder::OnResetDone() {
   DCHECK(pending_request_);
   DCHECK_EQ(pending_request_->type, Request::Type::kReset);
 
-  pending_request_.Release()->resolver.Release()->Resolve();
+  pending_request_.Release();
   ProcessRequests();
 }
 

third_party/blink/renderer/modules/webcodecs/video_decoder.h

@@ -43,11 +43,10 @@ class MODULES_EXPORT VideoDecoder final : public ScriptWrappable {
 
   // video_decoder.idl implementation.
   int32_t decodeQueueSize();
-  int32_t decodeProcessingCount();
-  ScriptPromise configure(const EncodedVideoConfig*, ExceptionState&);
-  ScriptPromise decode(const EncodedVideoChunk*, ExceptionState&);
+  void configure(const EncodedVideoConfig*, ExceptionState&);
+  void decode(const EncodedVideoChunk*, ExceptionState&);
   ScriptPromise flush(ExceptionState&);
-  ScriptPromise reset(ExceptionState&);
+  void reset(ExceptionState&);
 
   // GarbageCollected override.
   void Trace(Visitor*) const override;
@@ -64,8 +63,14 @@ class MODULES_EXPORT VideoDecoder final : public ScriptWrappable {
     void Trace(Visitor*) const;
 
     Type type;
+
+    // For kConfigure Requests.
     Member<const EncodedVideoConfig> config;
+
+    // For kDecode Requests.
     Member<const EncodedVideoChunk> chunk;
+
+    // For kFlush Requests.
     Member<ScriptPromiseResolver> resolver;
   };
 

third_party/blink/renderer/modules/webcodecs/video_decoder.idl

@@ -21,69 +21,50 @@
   // When in an error state, methods other than reset() will fail.
   //
   // TODO(sandersd): Consider adding a state or last error attribute.
-  // TODO(sandersd): Consider aborting pending decodes on error, rather than
-  // waiting for reset().
   [CallWith=ScriptState, RaisesException] constructor(VideoDecoderInit init);
 
-  // The number of queued decode requests. This does not include requests that
-  // have been taken for processing.
+  // The number of pending decode requests. This does not include requests that
+  // have been sent to the underlying codec.
   //
   // Applications can minimize underflow by enqueueing decode requests until
   // |decodeQueueSize| is greater than a constant.
-  readonly attribute long decodeQueueSize;
-
-  // The number of decode requests currently being processed.
   //
-  // Applications can minimize resource consumption and decode latency by
-  // enqueueing decode requests only when |decodeQueueSize| and
-  // |decodeProcessingCount| are small.
-  //
-  // TODO(sandersd): Consider counting queued decode requests as well. This
-  // could be simpler for apps.
-  readonly attribute long decodeProcessingCount;
+  // TODO(sandersd): Consider adding a predicted output count or other
+  // backpressure mechanism that considers the state of the underlying codec.
+  // TODO(sandersd): Consider emitting an event when this number decreases.
+  readonly attribute long decodeQueueSize;
 
-  // Enqueue a request to set or change the stream configuration.
+  // Set the stream configuration for future decode() requests.
   //
-  // The next enqueued decode request must be for a keyframe.
+  // The next decode request must be for a keyframe.
   //
-  // Resolved after emitting output for all earlier decode requests.
-  //
-  // TODO(sandersd): Test that resolution (a microtask) interleaves between
-  // outputs callback calls in all cases.
   // TODO(sandersd): Move the keyframe rule into the bytestream registry.
-  [RaisesException] Promise<void> configure(EncodedVideoConfig config);
+  [RaisesException] void configure(EncodedVideoConfig config);
 
-  // Enqueue a request to decode an input chunk.
-  //
-  // You must call configure() before calling enqueue() for the first time.
+  // Request decoding of an input chunk.
   //
-  // Resolved after decoding of the input chunk has started (that is, after
-  // decreasing |decodeQueueSize|).
+  // You must call configure() before calling decode() for the first time.
   //
   // TODO(sandersd): Change to a dictionary type.
-  // TODO(sandersd): Should we guarantee that resolution occurs in order?
-  // TODO(sandersd): Add status to result.
-  // TODO(sandersd): Buffer return.
-  [RaisesException] Promise<void> decode(EncodedVideoChunk chunk);
+  [RaisesException] void decode(EncodedVideoChunk chunk);
 
-  // Enqueue a request to finish decoding queued input chunks.
+  // Request output from all previous decode requests.
   //
-  // The next enqueued input chunk must be a keyframe.
+  // Resolved after all output for earlier decode requests has been emitted.
   //
-  // Resolved after emitting output for all earlier decode requests.
+  // The next decode request must be for a keyframe.
   //
   // TODO(sandersd): Consider relaxing the keyframe requirement.
+  // TODO(sandersd): Indicate whether the flush() completed successfully or due
+  // to a reset.
   [RaisesException] Promise<void> flush();
 
-  // Discard all pending work.
-  //
-  // Output for earlier decode requests will not be emitted, even if processing
-  // has already started.
-  //
-  // The next enqueued input chunk must be a keyframe.
+  // Discard all pending decode requests.
   //
-  // Resolved after all earlier enqueue() promises have been resolved.
+  // The next decode request must be for a keyframe.
   //
-  // TODO(sandersd): Require configure() after reset()?
-  [RaisesException] Promise<void> reset();
+  // Note: It may be possible to call reset() after a flush() promise has been
+  // resolved but before it is fulfilled. In that case the flush() promise will
+  // be fulfilled successfully even though reset() was called.
+  [RaisesException] void reset();
 };

third_party/blink/web_tests/webexposed/global-interface-listing-expected.txt

@@ -8720,7 +8720,6 @@ interface ValidityState
     method constructor
 interface VideoDecoder
     attribute @@toStringTag
-    getter decodeProcessingCount
     getter decodeQueueSize
     method configure
     method constructor