iOS: Move AppRTC logging methods to public headers.

BUG=

Review URL: https://codereview.webrtc.org/1241283004

Cr-Commit-Position: refs/heads/master@{#9629}
diff --git a/talk/examples/objc/AppRTCDemo/common/ARDUtilities.m b/talk/examples/objc/AppRTCDemo/common/ARDUtilities.m
index 066ee02..39010da 100644
--- a/talk/examples/objc/AppRTCDemo/common/ARDUtilities.m
+++ b/talk/examples/objc/AppRTCDemo/common/ARDUtilities.m
@@ -25,9 +25,10 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#import "ARDLogging.h"
 #import "ARDUtilities.h"
 
+#import "RTCLogging.h"
+
 @implementation NSDictionary (ARDUtilites)
 
 + (NSDictionary *)dictionaryWithJSONString:(NSString *)jsonString {
@@ -37,7 +38,7 @@
   NSDictionary *dict =
       [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
   if (error) {
-    ARDLog(@"Error parsing JSON: %@", error.localizedDescription);
+    RTCLogError(@"Error parsing JSON: %@", error.localizedDescription);
   }
   return dict;
 }
@@ -47,7 +48,7 @@
   NSDictionary *dict =
       [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];
   if (error) {
-    ARDLog(@"Error parsing JSON: %@", error.localizedDescription);
+    RTCLogError(@"Error parsing JSON: %@", error.localizedDescription);
   }
   return dict;
 }
@@ -85,7 +86,7 @@
                                     NSData *data,
                                     NSError *error) {
     if (error) {
-      ARDLog(@"Error posting data: %@", error.localizedDescription);
+      RTCLogError(@"Error posting data: %@", error.localizedDescription);
       if (completionHandler) {
         completionHandler(NO, data);
       }
@@ -96,7 +97,7 @@
       NSString *serverResponse = data.length > 0 ?
           [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] :
           nil;
-      ARDLog(@"Received bad response: %@", serverResponse);
+      RTCLogError(@"Received bad response: %@", serverResponse);
       if (completionHandler) {
         completionHandler(NO, data);
       }