16 bpp video stream capture, render and createImageBitmap(video) using (CPU) shared memory buffers

cc/resources/video_resource_updater.cc

 // Copyright 2013 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 "cc/resources/video_resource_updater.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 340 matching lines @@
     case media::PIXEL_FORMAT_YUV420P12:
     case media::PIXEL_FORMAT_YUV422P12:
     case media::PIXEL_FORMAT_YUV444P12:
       bits_per_channel = 12;
       break;
     case media::PIXEL_FORMAT_Y16:
       bits_per_channel = 16;
       break;
   }
 
-  // TODO(dshwang): support PIXEL_FORMAT_Y16. crbug.com/624436
-  DCHECK_NE(bits_per_channel, 16);
-
-  // Only YUV software video frames are supported.
-  if (!media::IsYuvPlanar(input_frame_format)) {
+  // Only YUV and Y16 software video frames are supported.
+  const bool isYuvPlanar = media::IsYuvPlanar(input_frame_format);
+  if (!(isYuvPlanar || input_frame_format == media::PIXEL_FORMAT_Y16)) {
     NOTREACHED() << media::VideoPixelFormatToString(input_frame_format);
     return VideoFrameExternalResources();
   }
 
   const bool software_compositor = context_provider_ == NULL;
 
   ResourceFormat output_resource_format =
-      resource_provider_->YuvResourceFormat(bits_per_channel);
+      isYuvPlanar ? resource_provider_->YuvResourceFormat(bits_per_channel)

[aleksandar.stojiljkovic, 2016/10/20 21:52:49]

Check above only allows Yuv and Y16, so ResourceFormat::RGBA_8888 is the same as
if checking Y16, at least for now.
In following patches, the plan is to add also Y8 but this line wouldn't change -
Y8 would either use the same as lowbit YUV (R8) or RGBA_8888 here.
GPU buffer support is part of original patch and it is planned to submit it
later, once the discussion about what GPU format to use for Y16 is over.

+                  : ResourceFormat::RGBA_8888;
 
   // If GPU compositing is enabled, but the output resource format
   // returned by the resource provider is RGBA_8888, then a GPU driver
   // bug workaround requires that YUV frames must be converted to RGB
   // before texture upload.
   bool texture_needs_rgb_conversion =
       !software_compositor &&
       output_resource_format == ResourceFormat::RGBA_8888;
   size_t output_plane_count = media::VideoFrame::NumPlanes(input_frame_format);
 
@@ skipping 379 matching lines @@
   if (lost_resource) {
     resource_it->clear_refs();
     updater->DeleteResource(resource_it);
     return;
   }
 
   resource_it->remove_ref();
 }
 
 }  // namespace cc