Add an additional VDA::Flush() mode to return all allocated buffers.

content/common/gpu/media/v4l2_video_decode_accelerator.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <dlfcn.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/videodev2.h>
 #include <poll.h>
 #include <string.h>
@@ skipping 204 matching lines @@
   if (config.is_encrypted) {
     NOTREACHED() << "Encrypted streams are not supported for this VDA";
     return false;
   }
 
   if (config.output_mode != Config::OutputMode::ALLOCATE) {
     NOTREACHED() << "Only ALLOCATE OutputMode is supported by this VDA";
     return false;
   }
 
+  if (config.flush_mode != Config::FlushMode::KEEP_OUTPUT_BUFFERS) {
+    NOTIMPLEMENTED() << "Modes other than KEEP_OUTPUT_BUFFERS not implemented";
+    return false;
+  }
+
   if (get_gl_context_cb_.is_null() || make_context_current_cb_.is_null()) {
     NOTREACHED() << "GL callbacks are required for this VDA";
     return false;
   }
 
   client_ptr_factory_.reset(new base::WeakPtrFactory<Client>(client));
   client_ = client_ptr_factory_->GetWeakPtr();
   // If we haven't been set up to decode on separate thread via
   // TryToSetupDecodeOnSeparateThread(), use the main thread/client for
   // decode tasks.
@@ skipping 1829 matching lines @@
 
 void V4L2VideoDecodeAccelerator::PictureCleared() {
   DVLOG(3) << "PictureCleared(). clearing count=" << picture_clearing_count_;
   DCHECK_EQ(decoder_thread_.message_loop(), base::MessageLoop::current());
   DCHECK_GT(picture_clearing_count_, 0);
   picture_clearing_count_--;
   SendPictureReady();
 }
 
 }  // namespace content