Enables fullscreen subtitle and media control from Blink

content/public/browser/android/compositor.h

Index: content/public/browser/android/compositor.h
diff --git a/content/public/browser/android/compositor.h b/content/public/browser/android/compositor.h
index eb0c96e6413539116aad6f9d0dd159e0e2ca2a94..0a96af555783a25f2c58dc31705976221cb564cd 100644
--- a/content/public/browser/android/compositor.h
+++ b/content/public/browser/android/compositor.h
@@ -61,6 +61,9 @@ class CONTENT_EXPORT Compositor {
   // Set the output surface which the compositor renders into.
   virtual void SetSurface(jobject surface) = 0;
 
+  // Tells the view tree to assume a transparent background when rendering.
+  virtual void SetHasTransparentBackground(bool flag) = 0;
+
   // Attempts to composite and read back the result into the provided buffer.
   // The buffer must be at least window width * height * 4 (RGBA) bytes large.
   // The buffer is not modified if false is returned.