Fix deprecated methods in AppRTCMobile.

Remove warning suppressions and update code that uses deprecated methods
to the currently supported APIs.

BUG=webrtc:5549

Review-Url: https://codereview.webrtc.org/2780433006
Cr-Commit-Position: refs/heads/master@{#17472}
diff --git a/webrtc/examples/objc/AppRTCMobile/ARDAppEngineClient.m b/webrtc/examples/objc/AppRTCMobile/ARDAppEngineClient.m
index d707b92..ad7a6c2 100644
--- a/webrtc/examples/objc/AppRTCMobile/ARDAppEngineClient.m
+++ b/webrtc/examples/objc/AppRTCMobile/ARDAppEngineClient.m
@@ -57,29 +57,26 @@
   request.HTTPMethod = @"POST";
   __weak ARDAppEngineClient *weakSelf = self;
   [NSURLConnection sendAsyncRequest:request
-                  completionHandler:^(NSURLResponse *response,
-                                      NSData *data,
-                                      NSError *error) {
-    ARDAppEngineClient *strongSelf = weakSelf;
-    if (error) {
-      if (completionHandler) {
-        completionHandler(nil, error);
-      }
-      return;
-    }
-    ARDJoinResponse *joinResponse =
-        [ARDJoinResponse responseFromJSONData:data];
-    if (!joinResponse) {
-      if (completionHandler) {
-        NSError *error = [[self class] badResponseError];
-        completionHandler(nil, error);
-      }
-      return;
-    }
-    if (completionHandler) {
-      completionHandler(joinResponse, nil);
-    }
-  }];
+                  completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
+                    ARDAppEngineClient *strongSelf = weakSelf;
+                    if (error) {
+                      if (completionHandler) {
+                        completionHandler(nil, error);
+                      }
+                      return;
+                    }
+                    ARDJoinResponse *joinResponse = [ARDJoinResponse responseFromJSONData:data];
+                    if (!joinResponse) {
+                      if (completionHandler) {
+                        NSError *error = [[self class] badResponseError];
+                        completionHandler(nil, error);
+                      }
+                      return;
+                    }
+                    if (completionHandler) {
+                      completionHandler(joinResponse, nil);
+                    }
+                  }];
 }
 
 - (void)sendMessage:(ARDSignalingMessage *)message
@@ -138,17 +135,24 @@
   NSURL *url = [NSURL URLWithString:urlString];
   NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
   request.HTTPMethod = @"POST";
-  NSURLResponse *response = nil;
-  NSError *error = nil;
+
+  RTCLog(@"C->RS: BYE");
+  __block NSError *error = nil;
+
   // We want a synchronous request so that we know that we've left the room on
   // room server before we do any further work.
-  RTCLog(@"C->RS: BYE");
-  [NSURLConnection sendSynchronousRequest:request
-                        returningResponse:&response
-                                    error:&error];
+  dispatch_semaphore_t sem = dispatch_semaphore_create(0);
+  [NSURLConnection sendAsyncRequest:request
+                  completionHandler:^(NSURLResponse *response, NSData *data, NSError *e) {
+                    if (e) {
+                      error = e;
+                    }
+                    dispatch_semaphore_signal(sem);
+                  }];
+
+  dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER);
   if (error) {
-    RTCLogError(@"Error leaving room %@ on room server: %@",
-          roomId, error.localizedDescription);
+    RTCLogError(@"Error leaving room %@ on room server: %@", roomId, error.localizedDescription);
     if (completionHandler) {
       completionHandler(error);
     }