Support external buffer import in VDA interface and add a V4L2SVDA impl.

content/common/gpu/media/vt_video_decode_accelerator_mac.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 <algorithm>
 
 #include <CoreVideo/CoreVideo.h>
 #include <OpenGL/CGLIOSurface.h>
 #include <OpenGL/gl.h>
 #include <stddef.h>
@@ skipping 303 matching lines @@
   if (make_context_current_cb_.is_null() || bind_image_cb_.is_null()) {
     NOTREACHED() << "GL callbacks are required for this VDA";
     return false;
   }
 
   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;
+  }
+
   client_ = client;
 
   if (!InitializeVideoToolbox())
     return false;
 
   bool profile_supported = false;
   for (const auto& supported_profile : kSupportedProfiles) {
     if (config.profile == supported_profile) {
       profile_supported = true;
       break;
@@ skipping 806 matching lines @@
     SupportedProfile profile;
     profile.profile = supported_profile;
     profile.min_resolution.SetSize(16, 16);
     profile.max_resolution.SetSize(4096, 2160);
     profiles.push_back(profile);
   }
   return profiles;
 }
 
 }  // namespace content