Enable iOS AppRTCDemo send side BWE.

webrtc/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m

Index: webrtc/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m
diff --git a/webrtc/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m b/webrtc/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m
index d815008caee48037bf55168bff7899196af800f6..48d7404ddb86d2d4403940671650dd830d92ab49 100644
--- a/webrtc/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m
+++ b/webrtc/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m
@@ -10,6 +10,7 @@
 
 #import "ARDAppDelegate.h"
 
+#import "webrtc/base/objc/RTCFieldTrials.h"
 #import "webrtc/base/objc/RTCTracing.h"
 #import "RTCLogging.h"
 #import "RTCPeerConnectionFactory.h"
@@ -25,6 +26,7 @@
 - (BOOL)application:(UIApplication *)application
     didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   [RTCPeerConnectionFactory initializeSSL];
+  RTCInitFieldTrials(RTCFieldTrialOptionsSendSideBwe);

[Chuck, 2016/03/03 14:37:59]

Just a question, the comment says this must be called before any other WebRTC
method, but this call is after RTCPeerConnectioNFactory initializeSSL.

[tkchin_webrtc, 2016/03/03 17:58:41]

Yeah, that actually isn't a "WebRTC" method. It just loads/initializes the SSL
library.
The reason it needs to be called before WebRTC stuff is because options for
field trials get loaded on init, so if you call it after init it does nothing.
Essentially as long as you init field trials before you create a
peerconnectionfactory instance you should be fine.
Unless we decide to add a field trial to the SSL init method.
Anyway, moving it up to prevent confusion.

   RTCSetupInternalTracer();
   _window =  [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
   [_window makeKeyAndVisible];