Bug 1656642 - part2 : prevent to start controller for non-playable media even if it enters fullscreen/PIP mode. r=chunmin

When a media without src or with error enters fullscreen or PIP mode, we don't want to control it. Therefore, we shouldn't start the listener for it.

In addition, updating PIP/fullscreen state no matter the listener starts or not. See following example.

1. Play a media and it enter PIP/fullscreen (it would update `state=true`)
2. abort the current src (that would stop the listener)
3. leave PIP/fullscreen (in this case, we don't have src, so the listener won't start, but we still need to update the `state` to `false`)

Differential Revision: https://phabricator.services.mozilla.com/D85785

dom/html/HTMLMediaElement.cpp

@@ -6656,9 +6656,11 @@ void HTMLMediaElement::NotifyFullScreenChanged() {
   const bool isInFullScreen = IsInFullScreen();
   if (isInFullScreen) {
     StartMediaControlKeyListenerIfNeeded();
-    MOZ_ASSERT(mMediaControlKeyListener->IsStarted(),
-               "Failed to start the listener when entering fullscreen!");
+    if (!mMediaControlKeyListener->IsStarted()) {
+      MEDIACONTROL_LOG("Failed to start the listener when entering fullscreen");
+    }
   }
+  // Updating controller fullscreen state no matter the listener starts or not.
   BrowsingContext* bc = OwnerDoc()->GetBrowsingContext();
   if (RefPtr<IMediaInfoUpdater> updater = ContentMediaAgent::Get(bc)) {
     updater->NotifyMediaFullScreenState(bc->Id(), isInFullScreen);
@@ -7919,7 +7921,16 @@ bool HTMLMediaElement::IsInFullScreen() const {
   return State().HasState(NS_EVENT_STATE_FULLSCREEN);
 }
 
+bool HTMLMediaElement::IsPlayable() const {
+  return (mDecoder || mSrcStream) && !HasError();
+}
+
 bool HTMLMediaElement::ShouldStartMediaControlKeyListener() const {
+  if (!IsPlayable()) {
+    MEDIACONTROL_LOG("Not start listener because media is not playable");
+    return false;
+  }
+
   if (IsBeingUsedInPictureInPictureMode()) {
     MEDIACONTROL_LOG("Start listener because of being used in PiP mode");
     return true;
@@ -7965,8 +7976,10 @@ void HTMLMediaElement::UpdateMediaControlAfterPictureInPictureModeChanged() {
     // When media enters PIP mode, we should ensure that the listener has been
     // started because we always want to control PIP video.
     StartMediaControlKeyListenerIfNeeded();
-    MOZ_ASSERT(mMediaControlKeyListener->IsStarted(),
-               "Failed to start listener when entering PIP mode");
+    if (!mMediaControlKeyListener->IsStarted()) {
+      MEDIACONTROL_LOG("Failed to start listener when entering PIP mode");
+    }
+    // Updating controller PIP state no matter the listener starts or not.
     mMediaControlKeyListener->SetPictureInPictureModeEnabled(true);
   } else {
     mMediaControlKeyListener->SetPictureInPictureModeEnabled(false);

dom/html/HTMLMediaElement.h

@@ -1932,6 +1932,10 @@ class HTMLMediaElement : public nsGenericHTMLElement,
   MozPromiseRequestHolder<ResumeDelayedPlaybackAgent::ResumePromise>
       mResumePlaybackRequest;
 
+  // Return true if we have already a decoder or a src stream and don't have any
+  // error.
+  bool IsPlayable() const;
+
   // Return true if the media qualifies for being controlled by media control
   // keys.
   bool ShouldStartMediaControlKeyListener() const;