Verify returned frames from media::VideoFrame::Wrap*() methods

chromecast/renderer/media/hole_frame_factory.cc

 // Copyright 2015 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 "chromecast/renderer/media/hole_frame_factory.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
@@ skipping 46 matching lines @@
   if (texture_) {
     scoped_refptr<::media::VideoFrame> frame =
         ::media::VideoFrame::WrapNativeTexture(
             ::media::PIXEL_FORMAT_XRGB,
             gpu::MailboxHolder(mailbox_, sync_token_, GL_TEXTURE_2D),
             ::media::VideoFrame::ReleaseMailboxCB(),
             size,                // coded_size
             gfx::Rect(size),     // visible rect
             size,                // natural size
             base::TimeDelta());  // timestamp
+    if (!frame)
+      return nullptr;

[halliwell, 2016/01/15 01:52:04]

I'm not sure how useful this is.  If there is a problem here, it just pushes the
problem out a level.

This is a hardcoded simple placeholder frame used only to carry the overlay
information to the browser compositor.  It does not carry any actual video data.

If we get a nullptr here then nothing is going to function correctly.  I would
say let's CHECK that frame is valid instead.

[emircan, 2016/01/15 02:04:10]

Done.

     frame->metadata()->SetBoolean(::media::VideoFrameMetadata::ALLOW_OVERLAY,
                                   true);
     return frame;
   } else {
     // This case is needed for audio-only devices.
     return ::media::VideoFrame::CreateBlackFrame(gfx::Size(1, 1));
   }
 }
 
 }  // namespace media
 }  // namespace chromecast