Provide a WebContents API to discover the playback of a fullscreen video.

content/browser/media/media_web_contents_observer.cc

Index: content/browser/media/media_web_contents_observer.cc
diff --git a/content/browser/media/media_web_contents_observer.cc b/content/browser/media/media_web_contents_observer.cc
index 87d7670d71aa4ac5aae1a5a5e0ae738b00d66eec..6ac77cf1e5acc4c75f0fba14258a644e8a030526 100644
--- a/content/browser/media/media_web_contents_observer.cc
+++ b/content/browser/media/media_web_contents_observer.cc
@@ -31,7 +31,7 @@ MediaWebContentsObserver::MediaWebContentsObserver(WebContents* web_contents)
     : WebContentsObserver(web_contents),
       session_controllers_manager_(this) {}
 
-MediaWebContentsObserver::~MediaWebContentsObserver() {}
+MediaWebContentsObserver::~MediaWebContentsObserver() = default;
 
 void MediaWebContentsObserver::WebContentsDestroyed() {
   GetAudibleMetrics()->UpdateAudibleWebContentsState(web_contents(), false);
@@ -41,6 +41,9 @@ void MediaWebContentsObserver::RenderFrameDeleted(
     RenderFrameHost* render_frame_host) {
   ClearPowerSaveBlockers(render_frame_host);
   session_controllers_manager_.RenderFrameDeleted(render_frame_host);
+
+  if (fullscreen_dominant_video_.first.first == render_frame_host)
+    fullscreen_dominant_video_.first = MediaPlayerId(nullptr, 0);
 }
 
 void MediaWebContentsObserver::MaybeUpdateAudibleState() {
@@ -58,6 +61,29 @@ void MediaWebContentsObserver::MaybeUpdateAudibleState() {
       web_contents(), audio_stream_monitor->IsCurrentlyAudible());
 }
 
+bool MediaWebContentsObserver::HasActiveFullscreenDominantVideo() const {
+  DCHECK(web_contents()->IsFullscreen());
+
+  // First check if there is a fullscreen or dominant video registered.
+  if (fullscreen_dominant_video_.first.first == nullptr)
+    return false;
+  if (!fullscreen_dominant_video_.second.fullscreen &&
+      !fullscreen_dominant_video_.second.dominant) {
+    return false;
+  }
+
+  // It has to be active.
+  const auto& players =
+      active_video_players_.find(fullscreen_dominant_video_.first.first);
+  if (players == active_video_players_.end())
+    return false;
+  if (players->second.find(fullscreen_dominant_video_.first.second) ==
+      players->second.end())
+    return false;
+
+  return true;
+}
+
 bool MediaWebContentsObserver::OnMessageReceived(
     const IPC::Message& msg,
     RenderFrameHost* render_frame_host) {
@@ -70,6 +96,10 @@ bool MediaWebContentsObserver::OnMessageReceived(
     IPC_MESSAGE_HANDLER(MediaPlayerDelegateHostMsg_OnMediaPaused, OnMediaPaused)
     IPC_MESSAGE_HANDLER(MediaPlayerDelegateHostMsg_OnMediaPlaying,
                         OnMediaPlaying)
+    IPC_MESSAGE_HANDLER(MediaPlayerDelegateHostMsg_OnMediaFullscreenChange,
+                        OnMediaFullscreenChange)
+    IPC_MESSAGE_HANDLER(MediaPlayerDelegateHostMsg_OnMediaDominantChange,
+                        OnMediaDominantChange)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -156,6 +186,34 @@ void MediaWebContentsObserver::OnMediaPlaying(
                             id);
 }
 
+void MediaWebContentsObserver::OnMediaFullscreenChange(
+    RenderFrameHost* render_frame_host,
+    int delegate_id,
+    bool is_fullscreen) {
+  const MediaPlayerId id(render_frame_host, delegate_id);
+
+  if (fullscreen_dominant_video_.first == id) {
+    fullscreen_dominant_video_.second.fullscreen = is_fullscreen;
+  } else if (is_fullscreen) {
+    fullscreen_dominant_video_.first = id;
+    fullscreen_dominant_video_.second = FullscreenDominantInfo(true, false);
+  }
+}
+
+void MediaWebContentsObserver::OnMediaDominantChange(
+    RenderFrameHost* render_frame_host,
+    int delegate_id,
+    bool is_dominant) {
+  const MediaPlayerId id(render_frame_host, delegate_id);
+
+  if (fullscreen_dominant_video_.first == id) {
+    fullscreen_dominant_video_.second.dominant = is_dominant;
+  } else if (is_dominant) {
+    fullscreen_dominant_video_.first = id;
+    fullscreen_dominant_video_.second = FullscreenDominantInfo(false, true);
+  }
+}
+
 void MediaWebContentsObserver::ClearPowerSaveBlockers(
     RenderFrameHost* render_frame_host) {
   std::set<MediaPlayerId> removed_players;