Adding third_party/openh264 build files for encoding

build/config/features.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 contains Chrome-feature-related build flags (see ui.gni for
 # UI-related ones). These should theoretically be moved to the build files of
 # the features themselves.
 #
 # However, today we have many "bad" dependencies on some of these flags from,
 # e.g. base, so they need to be global to match the GYP configuration. Also,
@@ skipping 36 matching lines @@
   # If debug_devtools is set to true, JavaScript files for DevTools are stored
   # as is and loaded from disk. Otherwise, a concatenated file is stored in
   # resources.pak. It is still possible to load JS files from disk by passing
   # --debug-devtools cmdline switch.
   debug_devtools = false
 
   # Enables WebRTC.
   # TODO(GYP) make mac work.
   enable_webrtc = !is_ios && !is_mac
 
+  # Enable this to build OpenH264.
+  # CHECK THE OPENH264 LICENSE BEFORE BUILDING. The default value should be 0,
+  # the open source version of Chromium should not build this by default due to
+  # license and patent reasons.
+  use_openh264 = true

[phoglund_chromium, 2015/11/16 14:51:41]

Same here.

[phoglund_chromium, 2015/11/16 14:52:21]

Acknowledged.

[Dirk Pranke, 2015/11/17 02:54:19]

"The default value should be false", not 0.

Also, would we want these to default to true in an official build? If so, we
should
make that be the case rather than require anyone who wants an official build
to have to specify additional flags.
 

[Dirk Pranke, 2015/11/17 23:49:14]

One more comment ... we shouldn't be adding new settings to features.gni unless
they tend to affect targets globally (which this one doesn't). Can you move this
to its own standalone *.gni file and then include it as needed?

[hbos_chromium, 2015/11/18 15:55:03]

Done.

Did the corresponding thing for gyp.
+ openh264_args.gni: defaults use_openh264 to is_chrome_branded.
+ openh264_args.gypi: defaults use_openh264 to 1 if branding=="Chrome", else 0.

In both cases you can override the default value (GYP_DEFINES or gn args),
regardless of if you're building chrome or chromium.

+
   # Enables the Media Router.
   enable_media_router = !is_ios
 
   # Enables proprietary codecs and demuxers; e.g. H264, MOV, AAC, and MP3.
   # Android OS includes support for proprietary codecs regardless of building
   # Chromium or Google Chrome. We also ship Google Chrome and Chromecast with
   # proprietary codecs.
   proprietary_codecs = is_android || is_chrome_branded || is_chromecast
 
   # TODO(GYP) This should be enabled on ios as well.
@@ skipping 129 matching lines @@
 use_gconf = is_linux && !is_chromeos && !is_chromecast && !is_headless
 
 # Whether to back up data before sync.
 enable_pre_sync_backup = is_win || is_mac || (is_linux && !is_chromeos)
 
 # Enable WebVR support by default on Android
 # Still requires command line flag to access API
 enable_webvr = is_android
 
 use_gio = is_desktop_linux && !is_headless