enable subtitle support and the new fullscreen video

android_webview/lib/main/aw_main_delegate.cc

Index: android_webview/lib/main/aw_main_delegate.cc
diff --git a/android_webview/lib/main/aw_main_delegate.cc b/android_webview/lib/main/aw_main_delegate.cc
index 08b2c0ea04bd052232c1ad1ae8f500614d378157..1d5d5be765356c811576c94184089b09b142f2cc 100644
--- a/android_webview/lib/main/aw_main_delegate.cc
+++ b/android_webview/lib/main/aw_main_delegate.cc
@@ -75,6 +75,9 @@ bool AwMainDelegate::BasicStartupComplete(int* exit_code) {
   // File system API not supported (requires some new API; internal bug 6930981)
   cl->AppendSwitch(switches::kDisableFileSystem);
 
+  // Fullscreen video with subtitle is not yet supported.
+  cl->AppendSwitch(switches::kDisableOverlayFullscreenVideoSubtitle);
+
 #if defined(VIDEO_HOLE)
   // Support EME/L1 with hole-punching.
   cl->AppendSwitch(switches::kMediaDrmEnableNonCompositing);