Add video decoding methods in Decryptor and add DecryptingVideoDecoder.

media/base/filter_collection.cc

Index: media/base/filter_collection.cc
diff --git a/media/base/filter_collection.cc b/media/base/filter_collection.cc
index f0992026e50d200dac076e112379890750930d8d..ff277baac5a20965ca026caa7fcf20ec67dd6beb 100644
--- a/media/base/filter_collection.cc
+++ b/media/base/filter_collection.cc
@@ -71,8 +71,7 @@ void FilterCollection::SelectVideoRenderer(scoped_refptr<VideoRenderer>* out) {
   video_renderers_.pop_front();
 }
 
-FilterCollection::VideoDecoderList*
-FilterCollection::GetVideoDecoders() {
+FilterCollection::VideoDecoderList* FilterCollection::GetVideoDecoders() {
   return &video_decoders_;
 }