iOS: Add trendline filter to field trials.

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

 /*
  *  Copyright 2013 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.
  */
 
 #import "ARDAppDelegate.h"
 
 #import "WebRTC/RTCFieldTrials.h"
 #import "WebRTC/RTCLogging.h"
 #import "WebRTC/RTCSSLAdapter.h"
 #import "WebRTC/RTCTracing.h"
 
 #import "ARDMainViewController.h"
 
 @implementation ARDAppDelegate {
   UIWindow *_window;
 }
 
 #pragma mark - UIApplicationDelegate methods
 
 - (BOOL)application:(UIApplication *)application
     didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
-  RTCInitFieldTrials(RTCFieldTrialOptionsImprovedBitrateEstimate);
+  NSDictionary *fieldTrials = @{
+    kRTCFieldTrialImprovedBitrateEstimateKey: kRTCFieldTrialEnabledValue,
+  };
+  RTCInitFieldTrialDictionary(fieldTrials);
   RTCInitializeSSL();
   RTCSetupInternalTracer();
   _window =  [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
   [_window makeKeyAndVisible];
   ARDMainViewController *viewController = [[ARDMainViewController alloc] init];
 
   UINavigationController *root =
       [[UINavigationController alloc] initWithRootViewController:viewController];
   root.navigationBar.translucent = NO;
   _window.rootViewController = root;
 
 #if defined(NDEBUG)
   // In debug builds the default level is LS_INFO and in non-debug builds it is
   // disabled. Continue to log to console in non-debug builds, but only
   // warnings and errors.
   RTCSetMinDebugLogLevel(RTCLoggingSeverityWarning);
 #endif
 
   return YES;
 }
 
 - (void)applicationWillTerminate:(UIApplication *)application {
   RTCShutdownInternalTracer();
   RTCCleanupSSL();
 }
 
 @end