Move Picture-in-Picture icon to the bottom of overflow menu

According to UI review deck, the Picture-in-Picture icon should live at
the very bottom of the list in the overflow menu.

Test page: https://beaufortfrancois.github.io/sandbox/media/overflow-video.html
Screenshots: https://imgur.com/a/lnH1e

Bug: 726621
Change-Id: Id0075ec3524842200eacc315539233a494edc484
Reviewed-on: https://chromium-review.googlesource.com/916381Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536697}

third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp

@@ -576,12 +576,6 @@ void MediaControlsImpl::InitializeControls() {
   // overflow menu.
   overflow_list_->AppendChild(play_button_->CreateOverflowElement(
       new MediaControlPlayButtonElement(*this)));
-  if (RuntimeEnabledFeatures::PictureInPictureEnabled() && !IsModern() &&
-      MediaElement().IsHTMLVideoElement()) {
-    overflow_list_->AppendChild(
-        picture_in_picture_button_->CreateOverflowElement(
-            new MediaControlPictureInPictureButtonElement(*this)));
-  }
   overflow_list_->AppendChild(fullscreen_button_->CreateOverflowElement(
       new MediaControlFullscreenButtonElement(*this)));
   overflow_list_->AppendChild(download_button_->CreateOverflowElement(
@@ -593,6 +587,12 @@ void MediaControlsImpl::InitializeControls() {
   overflow_list_->AppendChild(
       toggle_closed_captions_button_->CreateOverflowElement(
           new MediaControlToggleClosedCaptionsButtonElement(*this)));
+  if (RuntimeEnabledFeatures::PictureInPictureEnabled() && !IsModern() &&
+      MediaElement().IsHTMLVideoElement()) {
+    overflow_list_->AppendChild(
+        picture_in_picture_button_->CreateOverflowElement(
+            new MediaControlPictureInPictureButtonElement(*this)));
+  }
 
   // Set the default CSS classes.
   UpdateCSSClassFromState();