Don't require VDAs to return all PictureBuffers at once.

media/video/video_decode_accelerator.cc

Index: media/video/video_decode_accelerator.cc
diff --git a/media/video/video_decode_accelerator.cc b/media/video/video_decode_accelerator.cc
index 7449a2aec7f56c087b59183c1d8f70494a077a65..f06ade302558023f2ad41b0bd3f3de6d24b2ecbd 100644
--- a/media/video/video_decode_accelerator.cc
+++ b/media/video/video_decode_accelerator.cc
@@ -30,8 +30,7 @@ GLenum VideoDecodeAccelerator::GetSurfaceInternalFormat() const {
 }
 
 VideoDecodeAccelerator::SupportedProfile::SupportedProfile()
-    : profile(media::VIDEO_CODEC_PROFILE_UNKNOWN) {
-}
+    : profile(media::VIDEO_CODEC_PROFILE_UNKNOWN), flags(kNoFlags) {}
 
 VideoDecodeAccelerator::SupportedProfile::~SupportedProfile() {
 }