Add flags to enable screen orientation lock for fullscreen video on Android.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index da25e25dba061bf6d295ac506f2598c0685f23fc..c65b5cb297e377bd7450ebee13e60199d29eaa03 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -462,6 +462,9 @@ WebPreferences RenderViewHostImpl::ComputeWebkitPrefs() {
 
 #if defined(OS_ANDROID)
   prefs.device_supports_mouse = false;
+
+  prefs.video_fullscreen_orientation_lock_enabled =
+      base::FeatureList::IsEnabled(media::kVideoFullscreenOrientationLock);
 #endif
 
   prefs.pointer_events_max_touch_points = ui::MaxTouchPoints();