Adding third_party/openh264 build files for encoding

build/gn_migration.gypi

 # Copyright (c) 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.
 
 # This file defines five targets that we are using to track the progress of the
 # GYP->GN migration:
 #
 # 'both_gn_and_gyp' lists what GN is currently capable of building and should
 # match the 'both_gn_and_gyp' target in //BUILD.gn.
 #
@@ skipping 504 matching lines @@
             '../testing/gtest.gyp:gtest_main',
             '../third_party/codesighs/codesighs.gyp:msdump2symdb',
             '../third_party/codesighs/codesighs.gyp:msmap2tsv',
             '../third_party/pdfium/samples/samples.gyp:pdfium_diff',
             '../win8/win8.gyp:metro_viewer',
           ],
         }],
         ['chromecast==1', {
           'dependencies': [
             '../chromecast/chromecast.gyp:cast_shell',
-          ]
-        }]
+          ],
+        }],
+        ['use_openh264==1', {
+          'dependencies': [
+            '../third_party/openh264/openh264.gyp:openh264_common',
+            '../third_party/openh264/openh264.gyp:openh264_processing',
+            '../third_party/openh264/openh264.gyp:openh264_encoder',
+            '../third_party/openh264/openh264.gyp:openh264_decoder',
+          ],
+        }],
       ],
     },
     {
       'target_name': 'gyp_remaining',
       'type': 'none',
       'conditions': [
         ['remoting==1', {
           'dependencies': [
             '../remoting/app_remoting_webapp.gyp:ar_sample_app',  # crbug.com/471916
           ],
@@ skipping 251 matching lines @@
         ['OS=="android" and target_arch != "x64"', {
           'dependencies': [
             '../third_party/android_platform/relocation_packer.gyp:android_relocation_packer_unittests#host'
           ],
         }],
       ],
     },
   ]
 }