Fix VideoToolbox backgrounding issues

webrtc/base/base.gyp

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 {
   'includes': [ '../build/common.gypi', ],
@@ skipping 33 matching lines @@
             'objc/RTCSSLAdapter.h',
             'objc/RTCSSLAdapter.mm',
             'objc/RTCTracing.h',
             'objc/RTCTracing.mm',
           ],
           'conditions': [
             ['OS=="ios"', {
               'sources': [
                 'objc/RTCCameraPreviewView.h',
                 'objc/RTCCameraPreviewView.m',
+                'objc/RTCUIApplication.h',
+                'objc/RTCUIApplication.mm',
               ],
               'all_dependent_settings': {
                 'xcode_settings': {
                   'OTHER_LDFLAGS': [
                     '-framework AVFoundation',
                   ],
                 },
               },
             }],
           ],
@@ skipping 680 matching lines @@
     },
     {
      'target_name': 'gtest_prod',
       'type': 'static_library',
       'sources': [
         'gtest_prod_util.h',
       ],
     },
   ],
 }