Adding third_party/openh264 build files for encoding

BUILD.gn

 # Copyright (c) 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
 import("//build/config/features.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
 import("//build_overrides/v8.gni")
 import("//media/media_options.gni")
+import("//third_party/openh264/openh264_args.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 declare_args() {
   # A list of extra dependencies to add to the root target. This allows a
   # checkout to add additional targets without explicitly changing any checked-
   # in files.
   root_extra_deps = []
@@ skipping 553 matching lines @@
     ]
   } else if (!is_android && !is_ios) {
     deps += [
       "//breakpad:symupload($host_toolchain)",
       "//media/cast:cast_unittests",
     ]
   }
   if (is_chromecast) {
     deps += [ "//chromecast:cast_shell" ]
   }
+
+  if (use_openh264) {
+    deps += [
+      "//third_party/openh264:openh264_common",
+      "//third_party/openh264:openh264_processing",
+      "//third_party/openh264:openh264_encoder",
+      "//third_party/openh264:openh264_decoder",
+    ]
+  }
 }
 
 group("gn_only") {
   testonly = true
 
   deps = []
 
   if (!is_ios && !is_chromecast) {
     deps += [ "//mandoline:all" ]
   }
@@ skipping 241 matching lines @@
       if (target_cpu == "x86") {
         deps += [
           # "//content/shell:crash_service_win64", TODO(GYP): crbug.com/537009
         ]
       }
     } else {
       deps += [ "//breakpad:minidump_stackwalk($host_toolchain)" ]
     }
   }
 }