Disable background video track behind a feature flag

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 
@@ skipping 1162 matching lines @@
   settings->setMainFrameResizesAreOrientationChanges(
       prefs.main_frame_resizes_are_orientation_changes);
 
   settings->setUseSolidColorScrollbars(prefs.use_solid_color_scrollbars);
 
   settings->setShowContextMenuOnMouseUp(prefs.context_menu_on_mouse_up);
   settings->setAlwaysShowContextMenuOnTouch(
       prefs.always_show_context_menu_on_touch);
 
   settings->setHideDownloadUI(prefs.hide_download_ui);
+  WebRuntimeFeatures::enableBackgroundVideoTrackOptimization(
+      prefs.background_video_track_optimization_enabled);
 
 #if defined(OS_MACOSX)
   settings->setDoubleTapToZoomEnabled(true);
   web_view->setMaximumLegibleScale(prefs.default_maximum_page_scale_factor);
 #endif
 
 #if defined(OS_WIN)
   WebRuntimeFeatures::enableMiddleClickAutoscroll(true);
 #endif
 }
@@ skipping 1783 matching lines @@
                             INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   }
 
   std::unique_ptr<InputEventAck> ack(
       new InputEventAck(InputEventAckSource::MAIN_THREAD, input_event->type,
                         INPUT_EVENT_ACK_STATE_NOT_CONSUMED));
   OnInputEventAck(std::move(ack));
 }
 
 }  // namespace content