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..9c6f3f05568341dfff61d78a96d3f6de1cd0c910 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 +41,11 @@ void MediaWebContentsObserver::RenderFrameDeleted(
     RenderFrameHost* render_frame_host) {
   ClearPowerSaveBlockers(render_frame_host);
   session_controllers_manager_.RenderFrameDeleted(render_frame_host);
+
+  if (fullscreen_player_.has_value() &&
+      fullscreen_player_->first == render_frame_host) {
+    fullscreen_player_.reset();
+  }
 }
 
 void MediaWebContentsObserver::MaybeUpdateAudibleState() {
@@ -58,6 +63,22 @@ void MediaWebContentsObserver::MaybeUpdateAudibleState() {
       web_contents(), audio_stream_monitor->IsCurrentlyAudible());
 }
 
+bool MediaWebContentsObserver::HasActiveEffectivelyFullscreenVideo() const {
+  DCHECK(web_contents()->IsFullscreen());
+
+  if (!fullscreen_player_.has_value())

[dcheng, 2017/02/23 03:18:52]

Nit: omit .has_value()

[mlamouri (slow - plz ping), 2017/02/23 13:34:18]

I actually like explicit has_value() but I guess implicit boolean conversion
should be fine :)

+    return false;
+
+  // Check that the player is active.
+  const auto& players = active_video_players_.find(fullscreen_player_->first);
+  if (players == active_video_players_.end())
+    return false;
+  if (players->second.find(fullscreen_player_->second) == players->second.end())
+    return false;
+
+  return true;
+}
+
 bool MediaWebContentsObserver::OnMessageReceived(
     const IPC::Message& msg,
     RenderFrameHost* render_frame_host) {
@@ -70,6 +91,9 @@ bool MediaWebContentsObserver::OnMessageReceived(
     IPC_MESSAGE_HANDLER(MediaPlayerDelegateHostMsg_OnMediaPaused, OnMediaPaused)
     IPC_MESSAGE_HANDLER(MediaPlayerDelegateHostMsg_OnMediaPlaying,
                         OnMediaPlaying)
+    IPC_MESSAGE_HANDLER(
+        MediaPlayerDelegateHostMsg_OnMediaEffectivelyFullscreenChange,
+        OnMediaEffectivelyFullscreenChange)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -156,6 +180,21 @@ void MediaWebContentsObserver::OnMediaPlaying(
                             id);
 }
 
+void MediaWebContentsObserver::OnMediaEffectivelyFullscreenChange(
+    RenderFrameHost* render_frame_host,
+    int delegate_id,
+    bool is_fullscreen) {
+  const MediaPlayerId id(render_frame_host, delegate_id);
+
+  if (!is_fullscreen) {
+    if (fullscreen_player_.has_value() && *fullscreen_player_ == id)

[dcheng, 2017/02/23 03:18:52]

Nit: combine the if statements and remove has_value()

[mlamouri (slow - plz ping), 2017/02/23 13:34:18]

Okay for has_value() but I can't combine the if statements as it would have a
side effect (fullscreen_player_ = id)

+      fullscreen_player_.reset();
+    return;
+  }
+
+  fullscreen_player_ = id;
+}
+
 void MediaWebContentsObserver::ClearPowerSaveBlockers(
     RenderFrameHost* render_frame_host) {
   std::set<MediaPlayerId> removed_players;