GpuVideoDecoder should reject playback of videos with alpha channel.

media/filters/gpu_video_decoder.cc

 // Copyright (c) 2012 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 "media/filters/gpu_video_decoder.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 166 matching lines @@
            << "GVD with config: " << config.AsHumanReadableString();
 
   // TODO(posciak): destroy and create a new VDA on codec/profile change
   // (http://crbug.com/260224).
   if (previously_initialized && (config_.profile() != config.profile())) {
     DVLOG(1) << "Codec or profile changed, cannot reinitialize.";
     bound_init_cb.Run(false);
     return;
   }
 
+  if (config.format() == PIXEL_FORMAT_YV12A) {

[sandersd (OOO until July 31), 2016/06/17 18:09:19]

Please add a TODO to move this to capabilities, since it is conceivable that
some platforms could support such things, or to expose it in VDA::Config so that
each VDA can decide.

Not also that VDA::Config recently got |supported_output_formats|, but its use
is the inverse of this.

[DaleCurtis, 2016/06/17 18:19:56]

Done.

+    DVLOG(1) << "Alpha transparency formats are not supported.";
+    bound_init_cb.Run(false);
+    return;
+  }
+
   VideoDecodeAccelerator::Capabilities capabilities =
       factories_->GetVideoDecodeAcceleratorCapabilities();
   if (!IsProfileSupported(capabilities, config.profile(), config.coded_size(),
                           config.is_encrypted())) {
     DVLOG(1) << "Unsupported profile " << config.profile()
              << ", unsupported coded size " << config.coded_size().ToString()
              << ", or accelerator should only be used for encrypted content. "
              << " is_encrypted: " << (config.is_encrypted() ? "yes." : "no.");
     bound_init_cb.Run(false);
     return;
@@ skipping 594 matching lines @@
   }
   return false;
 }
 
 void GpuVideoDecoder::DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent()
     const {
   DCHECK(factories_->GetTaskRunner()->BelongsToCurrentThread());
 }
 
 }  // namespace media