Move Hide() to RemovedFrom() for disconnected media controls.

Found when debugging nested remove() issue for CSS update roots.
Resolves TODO.

TEST=media/
TEST=external/wpt/media*

Bug: 868810
Change-Id: If2d13a9167ed331b562f55ca7e5a5802e7751362
Reviewed-on: https://chromium-review.googlesource.com/1202142Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588932}

third_party/blink/renderer/core/html/media/html_media_element.cc

@@ -720,7 +720,6 @@ void HTMLMediaElement::RemovedFrom(ContainerNode& insertion_point) {
 
   HTMLElement::RemovedFrom(insertion_point);
   if (insertion_point.InActiveDocument()) {
-    UpdateControlsVisibility();
     if (network_state_ > kNetworkEmpty)
       PauseInternal();
   }
@@ -3826,11 +3825,8 @@ void HTMLMediaElement::EnsureMediaControls() {
 }
 
 void HTMLMediaElement::UpdateControlsVisibility() {
-  if (!isConnected()) {
-    if (GetMediaControls())
-      GetMediaControls()->Hide();
+  if (!isConnected())
     return;
-  }
 
   bool native_controls = ShouldShowControls(RecordMetricsBehavior::kDoRecord);
 

third_party/blink/renderer/modules/media_controls/media_controls_impl.cc

@@ -813,8 +813,7 @@ void MediaControlsImpl::RemovedFrom(ContainerNode& insertion_point) {
 
   HTMLDivElement::RemovedFrom(insertion_point);
 
-  // TODO(mlamouri): we hide show the controls instead of having
-  // HTMLMediaElement do it.
+  Hide();
 
   media_event_listener_->Detach();
   if (orientation_lock_delegate_)