Reset picture_in_picture_allowed_in_fullscreen_ when fullscreen_player_ is reset.

This is an opportunistic fix for a crash that we were not able to
reproduce locally.

Bug: 833360
Change-Id: If376405dd75591bcbbb47273e2330027de8ebd0d
Reviewed-on: https://chromium-review.googlesource.com/1028359Reviewed-by: Frank Liberato <liberato@chromium.org>
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553680}

content/browser/media/media_web_contents_observer.cc

@@ -69,10 +69,10 @@ void MediaWebContentsObserver::RenderFrameDeleted(
   ClearWakeLocks(render_frame_host);
   session_controllers_manager_.RenderFrameDeleted(render_frame_host);
 
-  if (fullscreen_player_ && fullscreen_player_->first == render_frame_host)
-    fullscreen_player_.reset();
-
+  if (fullscreen_player_ && fullscreen_player_->first == render_frame_host) {
     picture_in_picture_allowed_in_fullscreen_.reset();
+    fullscreen_player_.reset();
+  }
 }
 
 void MediaWebContentsObserver::MaybeUpdateAudibleState() {
@@ -274,10 +274,10 @@ void MediaWebContentsObserver::OnMediaEffectivelyFullscreenChanged(
       picture_in_picture_allowed_in_fullscreen_ = false;
       break;
     case blink::WebFullscreenVideoStatus::kNotEffectivelyFullscreen:
-      picture_in_picture_allowed_in_fullscreen_.reset();
       if (!fullscreen_player_ || *fullscreen_player_ != id)
         return;
 
+      picture_in_picture_allowed_in_fullscreen_.reset();
       fullscreen_player_.reset();
       break;
   }