Bug 1543122 - Add a privileged UAWidget-accessible WebIDL API for triggering Picture-in-Picture. r=jya,Ehsan

Differential Revision: https://phabricator.services.mozilla.com/D26777

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

dom/html/HTMLVideoElement.cpp

@@ -548,5 +548,15 @@ void HTMLVideoElement::EndCloningVisually() {
   }
 }
 
+void HTMLVideoElement::TogglePictureInPicture(ErrorResult& error) {
+  // The MozTogglePictureInPicture event is listen for via the
+  // PictureInPictureChild actor, which is responsible for opening the new
+  // window and starting the visual clone.
+  nsresult rv = DispatchEvent(NS_LITERAL_STRING("MozTogglePictureInPicture"));
+  if (NS_FAILED(rv)) {
+    error.Throw(rv);
+  }
+}
+
 }  // namespace dom
 }  // namespace mozilla

dom/html/HTMLVideoElement.h

@@ -145,6 +145,8 @@ class HTMLVideoElement final : public HTMLMediaElement {
 
   bool IsCloningElementVisually() const { return !!mVisualCloneTarget; }
 
+  void TogglePictureInPicture(ErrorResult& rv);
+
  protected:
   virtual ~HTMLVideoElement();
 

dom/webidl/HTMLVideoElement.webidl

@@ -69,6 +69,12 @@ partial interface HTMLVideoElement {
   // <video> element (see cloneElementVisually).
   [Func="IsChromeOrXBLOrUAWidget"]
     readonly attribute boolean isCloningElementVisually;
+
+  // Fires the privileged MozTogglePictureInPicture event to enter
+  // Picture-in-Picture. Call this when triggering Picture-in-Picture
+  // from the video controls UAWidget.
+  [Throws, Func="IsChromeOrXBLOrUAWidget"]
+    void togglePictureInPicture();
 };
 
 // https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#idl-def-HTMLVideoElement