MediaSessionAction message from embedder to script thread

components/compositing/windowing.rs

@@ -10,7 +10,7 @@ use euclid::Scale;
 use gleam::gl;
 use keyboard_types::KeyboardEvent;
 use msg::constellation_msg::{PipelineId, TopLevelBrowsingContextId, TraversalDirection};
-use script_traits::{MouseButton, TouchEventType, TouchId, WheelDelta};
+use script_traits::{MediaSessionActionType, MouseButton, TouchEventType, TouchId, WheelDelta};
 use servo_geometry::DeviceIndependentPixel;
 use servo_media::player::context::{GlApi, GlContext, NativeDisplay};
 use servo_url::ServoUrl;
@@ -102,6 +102,9 @@ pub enum WindowEvent {
     CaptureWebRender,
     /// Toggle sampling profiler with the given sampling rate and max duration.
     ToggleSamplingProfiler(Duration, Duration),
+    /// Sent when the user triggers a media action through the UA exposed media UI
+    /// (play, pause, seek, etc.).
+    MediaSessionAction(TopLevelBrowsingContextId, MediaSessionActionType),
 }
 
 impl Debug for WindowEvent {
@@ -132,6 +135,7 @@ impl Debug for WindowEvent {
             WindowEvent::CaptureWebRender => write!(f, "CaptureWebRender"),
             WindowEvent::ToggleSamplingProfiler(..) => write!(f, "ToggleSamplingProfiler"),
             WindowEvent::ExitFullScreen(..) => write!(f, "ExitFullScreen"),
+            WindowEvent::MediaSessionAction(..) => write!(f, "MediaSessionAction"),
         }
     }
 }

components/constellation/constellation.rs

@@ -139,7 +139,6 @@ use net_traits::{self, FetchResponseMsg, IpcSend, ResourceThreads};
 use profile_traits::mem;
 use profile_traits::time;
 use script_traits::CompositorEvent::{MouseButtonEvent, MouseMoveEvent};
-use script_traits::MouseEventType;
 use script_traits::{webdriver_msg, LogEntry, ScriptToConstellationChan, ServiceWorkerMsg};
 use script_traits::{
     AnimationState, AnimationTickType, AuxiliaryBrowsingContextLoadInfo, CompositorEvent,
@@ -154,6 +153,7 @@ use script_traits::{
 };
 use script_traits::{LayoutMsg as FromLayoutMsg, ScriptMsg as FromScriptMsg, ScriptThreadFactory};
 use script_traits::{MessagePortMsg, PortMessageTask, StructuredSerializedData};
+use script_traits::{MediaSessionActionType, MouseEventType};
 use script_traits::{SWManagerMsg, ScopeThings, UpdatePipelineIdReason, WebDriverCommandMsg};
 use serde::{Deserialize, Serialize};
 use servo_config::{opts, pref};
@@ -1541,6 +1541,9 @@ where
             FromCompositorMsg::ExitFullScreen(top_level_browsing_context_id) => {
                 self.handle_exit_fullscreen_msg(top_level_browsing_context_id);
             },
+            FromCompositorMsg::MediaSessionAction(top_level_browsing_context_id, action) => {
+                self.handle_media_session_action_msg(top_level_browsing_context_id, action);
+            },
         }
     }
 
@@ -5019,4 +5022,35 @@ where
                 .send(ToCompositorMsg::SetFrameTree(frame_tree));
         }
     }
+
+    fn handle_media_session_action_msg(
+        &mut self,
+        top_level_browsing_context_id: TopLevelBrowsingContextId,
+        action: MediaSessionActionType,
+    ) {
+        let browsing_context_id = BrowsingContextId::from(top_level_browsing_context_id);
+        let pipeline_id = match self.browsing_contexts.get(&browsing_context_id) {
+            Some(browsing_context) => browsing_context.pipeline_id,
+            None => {
+                return warn!(
+                    "Browsing context {} got media session action request after closure.",
+                    browsing_context_id
+                );
+            },
+        };
+        let msg =
+            ConstellationControlMsg::MediaSessionAction(top_level_browsing_context_id, action);
+        let result = match self.pipelines.get(&pipeline_id) {
+            None => {
+                return warn!(
+                    "Pipeline {} got media session action request after closure.",
+                    pipeline_id
+                )
+            },
+            Some(pipeline) => pipeline.event_loop.send(msg),
+        };
+        if let Err(e) = result {
+            self.handle_send_error(pipeline_id, e);
+        }
+    }
 }

components/script/script_thread.rs

@@ -139,7 +139,7 @@ use script_traits::{
     DiscardBrowsingContext, DocumentActivity, EventResult, HistoryEntryReplacement,
 };
 use script_traits::{InitialScriptState, JsEvalResult, LayoutMsg, LoadData, LoadOrigin};
-use script_traits::{MouseButton, MouseEventType, NewLayoutInfo};
+use script_traits::{MediaSessionActionType, MouseButton, MouseEventType, NewLayoutInfo};
 use script_traits::{Painter, ProgressiveWebMetricType, ScriptMsg, ScriptThreadFactory};
 use script_traits::{ScriptToConstellationChan, TimerEvent, TimerSchedulerMsg};
 use script_traits::{TimerSource, TouchEventType, TouchId, UntrustedNodeAddress, WheelDelta};
@@ -1720,6 +1720,7 @@ impl ScriptThread {
                     WebVREvents(id, ..) => Some(id),
                     PaintMetric(..) => None,
                     ExitFullScreen(id, ..) => Some(id),
+                    MediaSessionAction(..) => None,
                 }
             },
             MixedMessage::FromDevtools(_) => None,
@@ -1949,6 +1950,9 @@ impl ScriptThread {
             ConstellationControlMsg::PaintMetric(pipeline_id, metric_type, metric_value) => {
                 self.handle_paint_metric(pipeline_id, metric_type, metric_value)
             },
+            ConstellationControlMsg::MediaSessionAction(browsing_context_id, action) => {
+                self.handle_media_session_action(browsing_context_id, action)
+            },
             msg @ ConstellationControlMsg::AttachLayout(..) |
             msg @ ConstellationControlMsg::Viewport(..) |
             msg @ ConstellationControlMsg::SetScrollState(..) |
@@ -3932,6 +3936,14 @@ impl ScriptThread {
         }
     }
 
+    fn handle_media_session_action(
+        &self,
+        browsing_context_id: TopLevelBrowsingContextId,
+        action: MediaSessionActionType,
+    ) {
+        // TODO
+    }
+
     pub fn enqueue_microtask(job: Microtask) {
         SCRIPT_THREAD_ROOT.with(|root| {
             let script_thread = unsafe { &*root.get().unwrap() };

components/script_traits/lib.rs

@@ -388,6 +388,8 @@ pub enum ConstellationControlMsg {
     WebVREvents(PipelineId, Vec<WebVREvent>),
     /// Notifies the script thread about a new recorded paint metric.
     PaintMetric(PipelineId, ProgressiveWebMetricType, u64),
+    /// Notifies the media session about a user requested media session action.
+    MediaSessionAction(TopLevelBrowsingContextId, MediaSessionActionType),
 }
 
 impl fmt::Debug for ConstellationControlMsg {
@@ -426,6 +428,7 @@ impl fmt::Debug for ConstellationControlMsg {
             WebVREvents(..) => "WebVREvents",
             PaintMetric(..) => "PaintMetric",
             ExitFullScreen(..) => "ExitFullScreen",
+            MediaSessionAction(..) => "MediaSessionAction",
         };
         write!(formatter, "ConstellationControlMsg::{}", variant)
     }
@@ -877,6 +880,8 @@ pub enum ConstellationMsg {
     DisableProfiler,
     /// Request to exit from fullscreen mode
     ExitFullScreen(TopLevelBrowsingContextId),
+    /// Media session action.
+    MediaSessionAction(TopLevelBrowsingContextId, MediaSessionActionType),
 }
 
 impl fmt::Debug for ConstellationMsg {
@@ -907,6 +912,7 @@ impl fmt::Debug for ConstellationMsg {
             EnableProfiler(..) => "EnableProfiler",
             DisableProfiler => "DisableProfiler",
             ExitFullScreen(..) => "ExitFullScreen",
+            MediaSessionAction(..) => "MediaSessionAction",
         };
         write!(formatter, "ConstellationMsg::{}", variant)
     }
@@ -1052,4 +1058,32 @@ pub enum MessagePortMsg {
     RemoveMessagePort(MessagePortId),
     /// Handle a new port-message-task.
     NewTask(MessagePortId, PortMessageTask),
+
+/// The type of MediaSession action.
+/// https://w3c.github.io/mediasession/#enumdef-mediasessionaction
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub enum MediaSessionActionType {
+    /// The action intent is to resume playback.
+    Play,
+    /// The action intent is to pause the currently active playback.
+    Pause,
+    /// The action intent is to move the playback time backward by a short period (i.e. a few
+    /// seconds).
+    SeekBackward,
+    /// The action intent is to move the playback time forward by a short period (i.e. a few
+    /// seconds).
+    SeekForward,
+    /// The action intent is to either start the current playback from the beginning if the
+    /// playback has a notion, of beginning, or move to the previous item in the playlist if the
+    /// playback has a notion of playlist.
+    PreviousTrack,
+    /// The action is to move to the playback to the next item in the playlist if the playback has
+    /// a notion of playlist.
+    NextTrack,
+    /// The action intent is to skip the advertisement that is currently playing.
+    SkipAd,
+    /// The action intent is to stop the playback and clear the state if appropriate.
+    Stop,
+    /// The action intent is to move the playback time to a specific time.
+    SeekTo,
 }

components/servo/lib.rs

@@ -713,6 +713,16 @@ where
                     );
                 }
             },
+
+            WindowEvent::MediaSessionAction(ctx, a) => {
+                let msg = ConstellationMsg::MediaSessionAction(ctx, a);
+                if let Err(e) = self.constellation_chan.send(msg) {
+                    warn!(
+                        "Sending MediaSessionAction message to constellation failed ({:?}).",
+                        e
+                    );
+                }
+            },
         }
     }