Update iOS AppRTCDemo to use the updated Objective-C API.

webrtc/api/api.gyp

 # Copyright (c) 2015 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 222 matching lines @@
                 ],
               },
             }],
             ['OS=="mac"', {
               'sources': [
                 'objc/RTCNSGLVideoView.h',
                 'objc/RTCNSGLVideoView.m',
               ],
             }],
           ],
+          'all_dependent_settings': {
+            'xcode_settings': {
+              'CLANG_ENABLE_OBJC_ARC': 'YES',

[hjon_webrtc, 2016/02/12 17:34:56]

Is this how I should ensure ARC is enabled for apprtc_common, apprtc_signaling,
and AppRTCDemo? Or should I enable it for each of those targets individually?
This is how the current libjingle_peerconnection_objc seems to enable it, but at
least personally, enabling per target seems better.

+            },
+          },
           'xcode_settings': {
             'CLANG_ENABLE_OBJC_ARC': 'YES',
             'CLANG_WARN_OBJC_MISSING_PROPERTY_SYNTHESIS': 'YES',
             'GCC_PREFIX_HEADER': 'objc/WebRTC-Prefix.pch',
           },
         }
       ],
     }],  # OS=="ios"
   ],  # conditions
   'targets': [
@@ skipping 112 matching lines @@
               'AdditionalOptions': [
                 '-Wno-sign-compare',
               ],
             },
           },
         }],
       ],
     },  # target libjingle_peerconnection
   ],  # targets
 }