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

webrtc/api/api.gyp

Index: webrtc/api/api.gyp
diff --git a/webrtc/api/api.gyp b/webrtc/api/api.gyp
index 34a75f60f5eb6820193c7a6f2a087ea6ef16c7c6..c4ac92163310d841af0fe8187445689b93b6c925 100644
--- a/webrtc/api/api.gyp
+++ b/webrtc/api/api.gyp
@@ -240,6 +240,11 @@
               ],
             }],
           ],
+          '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',