[Android] A prototype of the interactive media notification.

content/content_browser.gypi

Index: content/content_browser.gypi
diff --git a/content/content_browser.gypi b/content/content_browser.gypi
index 0f3e00a3f575f9f916ff19fb440fa75eff2ac3e7..078fed3ad52faad3c8eeb8daed86bf094b975832 100644
--- a/content/content_browser.gypi
+++ b/content/content_browser.gypi
@@ -70,6 +70,8 @@
       'public/browser/android/devtools_auth.h',
       'public/browser/android/download_controller_android.h',
       'public/browser/android/external_video_surface_container.h',
+      'public/browser/android/media_controls_delegate.cc',
+      'public/browser/android/media_controls_delegate.h',
       'public/browser/android/synchronous_compositor.h',
       'public/browser/android/synchronous_compositor_client.h',
       'public/browser/appcache_service.h',