Clean up V4L2 codec-related flags and defines

content/common/common.gni

 # 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.
 
 # This file defines the content common gypi values. This file is read once and
 # cached, which is a performance optimization that allows us to share the
 # results of parsing the .gypi file between the public and private BUILD.gn
 # files. It also saves us from duplicating this exec_script call.
 content_common_gypi_values =
     exec_script("//build/gypi_to_gn.py",
                 [ rebase_path("../content_common.gypi") ],
                 "scope",
                 [ "../content_common.gypi" ])
 
 declare_args() {
-  # TODO(henryhsu): This flag should be removed after the linux header of
-  # trybot is updated.
+  # Indicates if V4L plugin is used.
+  use_v4lplugin = false
+
   # Indicates if Video4Linux2 codec is used. This is used for x86 CrOS

[wuchengli, 2015/01/21 12:50:42]

Update the comment. This will be used by both x86 and arm. Right?

[henryhsu, 2015/01/21 13:00:40]

No. The condition is (arm || (use_ozone && use_v4l2_codec)). So use_v4l2_codec
is only for x86 CrOS.

[Pawel Osciak, 2015/01/22 08:30:02]

Yes, but the name would be misleading then, and that's not the intention. I'd
rather we had use_v4l2_codec on all platforms, since it's used to save us from
non-CrOS builds, and should be enabled on all CrOS.

[henryhsu, 2015/01/22 09:09:09]

Done.

[Pawel Osciak, 2015/01/23 05:50:47]

If done, then I think we should not have to check for ARM for V4L2(S)VDA, but
for use_v4l2_codec instead?

   # platform which has v4l2 hardware encoder / decoder.
   use_v4l2_codec = false
 }