AppRTCDemo file logging.

Adds logging macros to log logs to a file. Undeletes CircularFileStream
for that purpose.

BUG=
R=jiayl@webrtc.org, pbos@webrtc.org

Review URL: https://codereview.webrtc.org/1217473011 .

Cr-Commit-Position: refs/heads/master@{#9582}
diff --git a/talk/examples/objc/.clang-format b/talk/examples/objc/.clang-format
new file mode 120000
index 0000000..ce43d52
--- /dev/null
+++ b/talk/examples/objc/.clang-format
@@ -0,0 +1 @@
+../../app/webrtc/objc/.clang-format
\ No newline at end of file
diff --git a/talk/examples/objc/AppRTCDemo/ARDAppClient.m b/talk/examples/objc/AppRTCDemo/ARDAppClient.m
index ac99ca2..5b905c6 100644
--- a/talk/examples/objc/AppRTCDemo/ARDAppClient.m
+++ b/talk/examples/objc/AppRTCDemo/ARDAppClient.m
@@ -30,6 +30,7 @@
 #if defined(WEBRTC_IOS)
 #import "RTCAVFoundationVideoSource.h"
 #endif
+#import "RTCFileLogger.h"
 #import "RTCICEServer.h"
 #import "RTCMediaConstraints.h"
 #import "RTCMediaStream.h"
@@ -41,6 +42,7 @@
 #import "ARDAppEngineClient.h"
 #import "ARDCEODTURNClient.h"
 #import "ARDJoinResponse.h"
+#import "ARDLogging.h"
 #import "ARDMessageResponse.h"
 #import "ARDSDPUtils.h"
 #import "ARDSignalingMessage.h"
@@ -65,7 +67,9 @@
 static NSInteger const kARDAppClientErrorInvalidClient = -5;
 static NSInteger const kARDAppClientErrorInvalidRoom = -6;
 
-@implementation ARDAppClient
+@implementation ARDAppClient {
+  RTCFileLogger *_fileLogger;
+}
 
 @synthesize delegate = _delegate;
 @synthesize state = _state;
@@ -131,6 +135,8 @@
   _factory = [[RTCPeerConnectionFactory alloc] init];
   _messageQueue = [NSMutableArray array];
   _iceServers = [NSMutableArray arrayWithObject:[self defaultSTUNServer]];
+  _fileLogger = [[RTCFileLogger alloc] init];
+  [_fileLogger start];
 }
 
 - (void)dealloc {
@@ -156,7 +162,7 @@
   [_turnClient requestServersWithCompletionHandler:^(NSArray *turnServers,
                                                      NSError *error) {
     if (error) {
-      NSLog(@"Error retrieving TURN servers: %@", error);
+      ARDLog("Error retrieving TURN servers: %@", error.localizedDescription);
     }
     ARDAppClient *strongSelf = weakSelf;
     [strongSelf.iceServers addObjectsFromArray:turnServers];
@@ -175,12 +181,12 @@
     NSError *joinError =
         [[strongSelf class] errorForJoinResultType:response.result];
     if (joinError) {
-      NSLog(@"Failed to join room:%@ on room server.", roomId);
+      ARDLog(@"Failed to join room:%@ on room server.", roomId);
       [strongSelf disconnect];
       [strongSelf.delegate appClient:strongSelf didError:joinError];
       return;
     }
-    NSLog(@"Joined room:%@ on room server.", roomId);
+    ARDLog(@"Joined room:%@ on room server.", roomId);
     strongSelf.roomId = response.roomId;
     strongSelf.clientId = response.clientId;
     strongSelf.isInitiator = response.isInitiator;
@@ -272,13 +278,13 @@
 
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     signalingStateChanged:(RTCSignalingState)stateChanged {
-  NSLog(@"Signaling state changed: %d", stateChanged);
+  ARDLog(@"Signaling state changed: %d", stateChanged);
 }
 
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
            addedStream:(RTCMediaStream *)stream {
   dispatch_async(dispatch_get_main_queue(), ^{
-    NSLog(@"Received %lu video tracks and %lu audio tracks",
+    ARDLog(@"Received %lu video tracks and %lu audio tracks",
         (unsigned long)stream.videoTracks.count,
         (unsigned long)stream.audioTracks.count);
     if (stream.videoTracks.count) {
@@ -290,17 +296,17 @@
 
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
         removedStream:(RTCMediaStream *)stream {
-  NSLog(@"Stream was removed.");
+  ARDLog(@"Stream was removed.");
 }
 
 - (void)peerConnectionOnRenegotiationNeeded:
     (RTCPeerConnection *)peerConnection {
-  NSLog(@"WARNING: Renegotiation needed but unimplemented.");
+  ARDLog(@"WARNING: Renegotiation needed but unimplemented.");
 }
 
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     iceConnectionChanged:(RTCICEConnectionState)newState {
-  NSLog(@"ICE state changed: %d", newState);
+  ARDLog(@"ICE state changed: %d", newState);
   dispatch_async(dispatch_get_main_queue(), ^{
     [_delegate appClient:self didChangeConnectionState:newState];
   });
@@ -308,7 +314,7 @@
 
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
     iceGatheringChanged:(RTCICEGatheringState)newState {
-  NSLog(@"ICE gathering state changed: %d", newState);
+  ARDLog(@"ICE gathering state changed: %d", newState);
 }
 
 - (void)peerConnection:(RTCPeerConnection *)peerConnection
@@ -333,7 +339,7 @@
                           error:(NSError *)error {
   dispatch_async(dispatch_get_main_queue(), ^{
     if (error) {
-      NSLog(@"Failed to create session description. Error: %@", error);
+      ARDLog(@"Failed to create session description. Error: %@", error);
       [self disconnect];
       NSDictionary *userInfo = @{
         NSLocalizedDescriptionKey: @"Failed to create session description.",
@@ -362,7 +368,7 @@
     didSetSessionDescriptionWithError:(NSError *)error {
   dispatch_async(dispatch_get_main_queue(), ^{
     if (error) {
-      NSLog(@"Failed to set session description. Error: %@", error);
+      ARDLog(@"Failed to set session description. Error: %@", error);
       [self disconnect];
       NSDictionary *userInfo = @{
         NSLocalizedDescriptionKey: @"Failed to set session description.",
diff --git a/talk/examples/objc/AppRTCDemo/ARDAppEngineClient.m b/talk/examples/objc/AppRTCDemo/ARDAppEngineClient.m
index 760a171..0b33325 100644
--- a/talk/examples/objc/AppRTCDemo/ARDAppEngineClient.m
+++ b/talk/examples/objc/AppRTCDemo/ARDAppEngineClient.m
@@ -28,6 +28,7 @@
 #import "ARDAppEngineClient.h"
 
 #import "ARDJoinResponse.h"
+#import "ARDLogging.h"
 #import "ARDMessageResponse.h"
 #import "ARDSignalingMessage.h"
 #import "ARDUtilities.h"
@@ -57,7 +58,7 @@
   NSString *urlString =
       [NSString stringWithFormat:kARDRoomServerJoinFormat, roomId];
   NSURL *roomURL = [NSURL URLWithString:urlString];
-  NSLog(@"Joining room:%@ on room server.", roomId);
+  ARDLog(@"Joining room:%@ on room server.", roomId);
   NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:roomURL];
   request.HTTPMethod = @"POST";
   __weak ARDAppEngineClient *weakSelf = self;
@@ -101,7 +102,7 @@
       [NSString stringWithFormat:
           kARDRoomServerMessageFormat, roomId, clientId];
   NSURL *url = [NSURL URLWithString:urlString];
-  NSLog(@"C->RS POST: %@", message);
+  ARDLog(@"C->RS POST: %@", message);
   NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
   request.HTTPMethod = @"POST";
   request.HTTPBody = data;
@@ -147,19 +148,19 @@
   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.
-  NSLog(@"C->RS: BYE");
+  ARDLog(@"C->RS: BYE");
   [NSURLConnection sendSynchronousRequest:request
                         returningResponse:&response
                                     error:&error];
   if (error) {
-    NSLog(@"Error leaving room %@ on room server: %@",
+    ARDLog(@"Error leaving room %@ on room server: %@",
           roomId, error.localizedDescription);
     if (completionHandler) {
       completionHandler(error);
     }
     return;
   }
-  NSLog(@"Left room:%@ on room server.", roomId);
+  ARDLog(@"Left room:%@ on room server.", roomId);
   if (completionHandler) {
     completionHandler(nil);
   }
diff --git a/talk/examples/objc/AppRTCDemo/ARDSDPUtils.m b/talk/examples/objc/AppRTCDemo/ARDSDPUtils.m
index 157d6fc..481b6ce 100644
--- a/talk/examples/objc/AppRTCDemo/ARDSDPUtils.m
+++ b/talk/examples/objc/AppRTCDemo/ARDSDPUtils.m
@@ -27,6 +27,7 @@
 
 #import "ARDSDPUtils.h"
 
+#import "ARDLogging.h"
 #import "RTCSessionDescription.h"
 
 @implementation ARDSDPUtils
@@ -42,7 +43,7 @@
   NSMutableArray *lines =
       [NSMutableArray arrayWithArray:
           [sdpString componentsSeparatedByString:lineSeparator]];
-  int mLineIndex = -1;
+  NSInteger mLineIndex = -1;
   NSString *codecRtpMap = nil;
   // a=rtpmap:<payload type> <encoding name>/<clock rate>
   // [/<encoding parameters>]
@@ -70,11 +71,11 @@
     }
   }
   if (mLineIndex == -1) {
-    NSLog(@"No m=video line, so can't prefer %@", codec);
+    ARDLog(@"No m=video line, so can't prefer %@", codec);
     return description;
   }
   if (!codecRtpMap) {
-    NSLog(@"No rtpmap for %@", codec);
+    ARDLog(@"No rtpmap for %@", codec);
     return description;
   }
   NSArray *origMLineParts =
@@ -98,7 +99,7 @@
     [lines replaceObjectAtIndex:mLineIndex
                      withObject:newMLine];
   } else {
-    NSLog(@"Wrong SDP media description format: %@", lines[mLineIndex]);
+    ARDLog(@"Wrong SDP media description format: %@", lines[mLineIndex]);
   }
   NSString *mangledSdpString = [lines componentsJoinedByString:lineSeparator];
   return [[RTCSessionDescription alloc] initWithType:description.type
diff --git a/talk/examples/objc/AppRTCDemo/ARDSignalingMessage.m b/talk/examples/objc/AppRTCDemo/ARDSignalingMessage.m
index e9fb09a..dc00e8f 100644
--- a/talk/examples/objc/AppRTCDemo/ARDSignalingMessage.m
+++ b/talk/examples/objc/AppRTCDemo/ARDSignalingMessage.m
@@ -27,6 +27,7 @@
 
 #import "ARDSignalingMessage.h"
 
+#import "ARDLogging.h"
 #import "ARDUtilities.h"
 #import "RTCICECandidate+JSON.h"
 #import "RTCSessionDescription+JSON.h"
@@ -52,7 +53,7 @@
 + (ARDSignalingMessage *)messageFromJSONString:(NSString *)jsonString {
   NSDictionary *values = [NSDictionary dictionaryWithJSONString:jsonString];
   if (!values) {
-    NSLog(@"Error parsing signaling message JSON.");
+    ARDLog(@"Error parsing signaling message JSON.");
     return nil;
   }
 
@@ -71,7 +72,7 @@
   } else if ([typeString isEqualToString:@"bye"]) {
     message = [[ARDByeMessage alloc] init];
   } else {
-    NSLog(@"Unexpected type: %@", typeString);
+    ARDLog(@"Unexpected type: %@", typeString);
   }
   return message;
 }
diff --git a/talk/examples/objc/AppRTCDemo/ARDWebSocketChannel.m b/talk/examples/objc/AppRTCDemo/ARDWebSocketChannel.m
index 27dd25d..f25e9d0 100644
--- a/talk/examples/objc/AppRTCDemo/ARDWebSocketChannel.m
+++ b/talk/examples/objc/AppRTCDemo/ARDWebSocketChannel.m
@@ -27,6 +27,7 @@
 
 #import "ARDWebSocketChannel.h"
 
+#import "ARDLogging.h"
 #import "ARDUtilities.h"
 #import "SRWebSocket.h"
 
@@ -57,7 +58,7 @@
     _delegate = delegate;
     _socket = [[SRWebSocket alloc] initWithURL:url];
     _socket.delegate = self;
-    NSLog(@"Opening WebSocket.");
+    ARDLog(@"Opening WebSocket.");
     [_socket open];
   }
   return self;
@@ -104,12 +105,12 @@
     NSString *messageString =
         [[NSString alloc] initWithData:messageJSONObject
                               encoding:NSUTF8StringEncoding];
-    NSLog(@"C->WSS: %@", messageString);
+    ARDLog(@"C->WSS: %@", messageString);
     [_socket send:messageString];
   } else {
     NSString *dataString =
         [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
-    NSLog(@"C->WSS POST: %@", dataString);
+    ARDLog(@"C->WSS POST: %@", dataString);
     NSString *urlString =
         [NSString stringWithFormat:@"%@/%@/%@",
             [_restURL absoluteString], _roomId, _clientId];
@@ -126,7 +127,7 @@
     return;
   }
   [_socket close];
-  NSLog(@"C->WSS DELETE rid:%@ cid:%@", _roomId, _clientId);
+  ARDLog(@"C->WSS DELETE rid:%@ cid:%@", _roomId, _clientId);
   NSString *urlString =
       [NSString stringWithFormat:@"%@/%@/%@",
           [_restURL absoluteString], _roomId, _clientId];
@@ -140,7 +141,7 @@
 #pragma mark - SRWebSocketDelegate
 
 - (void)webSocketDidOpen:(SRWebSocket *)webSocket {
-  NSLog(@"WebSocket connection opened.");
+  ARDLog(@"WebSocket connection opened.");
   self.state = kARDSignalingChannelStateOpen;
   if (_roomId.length && _clientId.length) {
     [self registerWithCollider];
@@ -154,24 +155,24 @@
                                                   options:0
                                                     error:nil];
   if (![jsonObject isKindOfClass:[NSDictionary class]]) {
-    NSLog(@"Unexpected message: %@", jsonObject);
+    ARDLog(@"Unexpected message: %@", jsonObject);
     return;
   }
   NSDictionary *wssMessage = jsonObject;
   NSString *errorString = wssMessage[kARDWSSMessageErrorKey];
   if (errorString.length) {
-    NSLog(@"WSS error: %@", errorString);
+    ARDLog(@"WSS error: %@", errorString);
     return;
   }
   NSString *payload = wssMessage[kARDWSSMessagePayloadKey];
   ARDSignalingMessage *signalingMessage =
       [ARDSignalingMessage messageFromJSONString:payload];
-  NSLog(@"WSS->C: %@", payload);
+  ARDLog(@"WSS->C: %@", payload);
   [_delegate channel:self didReceiveMessage:signalingMessage];
 }
 
 - (void)webSocket:(SRWebSocket *)webSocket didFailWithError:(NSError *)error {
-  NSLog(@"WebSocket error: %@", error);
+  ARDLog(@"WebSocket error: %@", error);
   self.state = kARDSignalingChannelStateError;
 }
 
@@ -179,7 +180,7 @@
     didCloseWithCode:(NSInteger)code
               reason:(NSString *)reason
             wasClean:(BOOL)wasClean {
-  NSLog(@"WebSocket closed with code: %ld reason:%@ wasClean:%d",
+  ARDLog(@"WebSocket closed with code: %ld reason:%@ wasClean:%d",
       (long)code, reason, wasClean);
   NSParameterAssert(_state != kARDSignalingChannelStateError);
   self.state = kARDSignalingChannelStateClosed;
@@ -204,7 +205,7 @@
                                         error:nil];
   NSString *messageString =
       [[NSString alloc] initWithData:message encoding:NSUTF8StringEncoding];
-  NSLog(@"Registering on WSS for rid:%@ cid:%@", _roomId, _clientId);
+  ARDLog(@"Registering on WSS for rid:%@ cid:%@", _roomId, _clientId);
   // Registration can fail if server rejects it. For example, if the room is
   // full.
   [_socket send:messageString];
diff --git a/talk/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m b/talk/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m
index c15d633..01d666d 100644
--- a/talk/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m
+++ b/talk/examples/objc/AppRTCDemo/RTCICECandidate+JSON.m
@@ -27,6 +27,8 @@
 
 #import "RTCICECandidate+JSON.h"
 
+#import "ARDLogging.h"
+
 static NSString const *kRTCICECandidateTypeKey = @"type";
 static NSString const *kRTCICECandidateTypeValue = @"candidate";
 static NSString const *kRTCICECandidateMidKey = @"id";
@@ -56,7 +58,7 @@
                                       options:NSJSONWritingPrettyPrinted
                                         error:&error];
   if (error) {
-    NSLog(@"Error serializing JSON: %@", error);
+    ARDLog(@"Error serializing JSON: %@", error);
     return nil;
   }
   return data;
diff --git a/talk/examples/objc/AppRTCDemo/common/ARDLogging.h b/talk/examples/objc/AppRTCDemo/common/ARDLogging.h
new file mode 100644
index 0000000..dfb31d8
--- /dev/null
+++ b/talk/examples/objc/AppRTCDemo/common/ARDLogging.h
@@ -0,0 +1,88 @@
+/*
+ * libjingle
+ * Copyright 2015 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#import <Foundation/Foundation.h>
+
+// We route all logging through the WebRTC logger. By doing this we will get
+// both app and WebRTC logs in the same place, which we can then route to a
+// file if we need to. A side effect of this is that we get severity for free.
+typedef NS_ENUM(NSInteger, ARDLogSeverity) {
+  kARDLogSeverityVerbose,
+  kARDLogSeverityInfo,
+  kARDLogSeverityWarning,
+  kARDLogSeverityError,
+};
+
+#if defined(__cplusplus)
+extern "C" void ARDLogToWebRTCLogger(ARDLogSeverity severity,
+                                     NSString *logString);
+extern "C" NSString *ARDFileName(const char *filePath);
+extern "C" void ARDLogInit();
+#else
+// Logs |logString| to the WebRTC logger at the given severity.
+extern void ARDLogToWebRTCLogger(ARDLogSeverity severity, NSString *logString);
+// Returns the filename with the path prefix removed.
+extern NSString *ARDFileName(const char *filePath);
+// Initializes the correct logging levels. This should be called once on app
+// startup.
+extern void ARDLogInit();
+#endif
+
+#define ARDLogString(format, ...)                    \
+  [NSString stringWithFormat:@"(%@:%d %s): " format, \
+      ARDFileName(__FILE__),                         \
+      __LINE__,                                      \
+      __FUNCTION__,                                  \
+      ##__VA_ARGS__]
+
+#define ARDLogEx(severity, format, ...)                        \
+  do {                                                         \
+    NSString *logString = ARDLogString(format, ##__VA_ARGS__); \
+    ARDLogToWebRTCLogger(severity, logString);                 \
+  } while (false)
+
+#define ARDLogVerbose(format, ...)                        \
+  ARDLogEx(kARDLogSeverityVerbose, format, ##__VA_ARGS__) \
+
+#define ARDLogInfo(format, ...)                           \
+  ARDLogEx(kARDLogSeverityInfo, format, ##__VA_ARGS__)    \
+
+#define ARDLogWarning(format, ...)                        \
+  ARDLogEx(kARDLogSeverityWarning, format, ##__VA_ARGS__) \
+
+#define ARDLogError(format, ...)                          \
+  ARDLogEx(kARDLogSeverityError, format, ##__VA_ARGS__)   \
+
+#ifdef _DEBUG
+#define ARDLogDebug(format, ...) ARDLogInfo(format, ##__VA_ARGS__)
+#else
+#define ARDLogDebug(format, ...) \
+  do {                           \
+  } while (false)
+#endif
+
+#define ARDLog(format, ...) ARDLogInfo(format, ##__VA_ARGS__)
diff --git a/talk/examples/objc/AppRTCDemo/common/ARDLogging.mm b/talk/examples/objc/AppRTCDemo/common/ARDLogging.mm
new file mode 100644
index 0000000..7bd773d
--- /dev/null
+++ b/talk/examples/objc/AppRTCDemo/common/ARDLogging.mm
@@ -0,0 +1,68 @@
+/*
+ * libjingle
+ * Copyright 2015 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#import "ARDLogging.h"
+
+#include "webrtc/base/logging.h"
+
+void ARDLogInit() {
+#ifndef _DEBUG
+  // 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.
+  rtc::LogMessage::LogToDebug(rtc::LS_WARNING);
+#endif
+}
+
+void ARDLogToWebRTCLogger(ARDLogSeverity severity, NSString *logString) {
+  if (logString.length) {
+    const char* utf8String = logString.UTF8String;
+    switch (severity) {
+      case kARDLogSeverityVerbose:
+        LOG(LS_VERBOSE) << utf8String;
+        break;
+      case kARDLogSeverityInfo:
+        LOG(LS_INFO) << utf8String;
+        break;
+      case kARDLogSeverityWarning:
+        LOG(LS_WARNING) << utf8String;
+        break;
+      case kARDLogSeverityError:
+        LOG(LS_ERROR) << utf8String;
+        break;
+    }
+  }
+}
+
+NSString *ARDFileName(const char *filePath) {
+  NSString *nsFilePath =
+      [[NSString alloc] initWithBytesNoCopy:const_cast<char *>(filePath)
+                                     length:strlen(filePath)
+                                   encoding:NSUTF8StringEncoding
+                               freeWhenDone:NO];
+  return nsFilePath.lastPathComponent;
+}
diff --git a/talk/examples/objc/AppRTCDemo/ARDUtilities.h b/talk/examples/objc/AppRTCDemo/common/ARDUtilities.h
similarity index 100%
rename from talk/examples/objc/AppRTCDemo/ARDUtilities.h
rename to talk/examples/objc/AppRTCDemo/common/ARDUtilities.h
diff --git a/talk/examples/objc/AppRTCDemo/ARDUtilities.m b/talk/examples/objc/AppRTCDemo/common/ARDUtilities.m
similarity index 93%
rename from talk/examples/objc/AppRTCDemo/ARDUtilities.m
rename to talk/examples/objc/AppRTCDemo/common/ARDUtilities.m
index 781e786..066ee02 100644
--- a/talk/examples/objc/AppRTCDemo/ARDUtilities.m
+++ b/talk/examples/objc/AppRTCDemo/common/ARDUtilities.m
@@ -25,6 +25,7 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#import "ARDLogging.h"
 #import "ARDUtilities.h"
 
 @implementation NSDictionary (ARDUtilites)
@@ -36,7 +37,7 @@
   NSDictionary *dict =
       [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
   if (error) {
-    NSLog(@"Error parsing JSON: %@", error.localizedDescription);
+    ARDLog(@"Error parsing JSON: %@", error.localizedDescription);
   }
   return dict;
 }
@@ -46,7 +47,7 @@
   NSDictionary *dict =
       [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];
   if (error) {
-    NSLog(@"Error parsing JSON: %@", error.localizedDescription);
+    ARDLog(@"Error parsing JSON: %@", error.localizedDescription);
   }
   return dict;
 }
@@ -84,7 +85,7 @@
                                     NSData *data,
                                     NSError *error) {
     if (error) {
-      NSLog(@"Error posting data: %@", error.localizedDescription);
+      ARDLog(@"Error posting data: %@", error.localizedDescription);
       if (completionHandler) {
         completionHandler(NO, data);
       }
@@ -95,7 +96,7 @@
       NSString *serverResponse = data.length > 0 ?
           [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] :
           nil;
-      NSLog(@"Received bad response: %@", serverResponse);
+      ARDLog(@"Received bad response: %@", serverResponse);
       if (completionHandler) {
         completionHandler(NO, data);
       }
diff --git a/talk/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m b/talk/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m
index 2a7a155..352ade6 100644
--- a/talk/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m
+++ b/talk/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m
@@ -27,6 +27,7 @@
 
 #import "ARDAppDelegate.h"
 
+#import "ARDLogging.h"
 #import "ARDMainViewController.h"
 #import "RTCPeerConnectionFactory.h"
 
@@ -43,6 +44,7 @@
   [_window makeKeyAndVisible];
   ARDMainViewController *viewController = [[ARDMainViewController alloc] init];
   _window.rootViewController = viewController;
+  ARDLogInit();
   return YES;
 }
 
diff --git a/talk/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.m b/talk/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.m
index 2f07c7a..149beef 100644
--- a/talk/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.m
+++ b/talk/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.m
@@ -30,6 +30,7 @@
 #import "RTCAVFoundationVideoSource.h"
 
 #import "ARDAppClient.h"
+#import "ARDLogging.h"
 #import "ARDVideoCallView.h"
 
 @interface ARDVideoCallViewController () <ARDAppClientDelegate,
@@ -69,13 +70,13 @@
     didChangeState:(ARDAppClientState)state {
   switch (state) {
     case kARDAppClientStateConnected:
-      NSLog(@"Client connected.");
+      ARDLog(@"Client connected.");
       break;
     case kARDAppClientStateConnecting:
-      NSLog(@"Client connecting.");
+      ARDLog(@"Client connecting.");
       break;
     case kARDAppClientStateDisconnected:
-      NSLog(@"Client disconnected.");
+      ARDLog(@"Client disconnected.");
       [self hangup];
       break;
   }
@@ -83,7 +84,7 @@
 
 - (void)appClient:(ARDAppClient *)client
     didChangeConnectionState:(RTCICEConnectionState)state {
-  NSLog(@"ICE state changed: %d", state);
+  ARDLog(@"ICE state changed: %d", state);
   __weak ARDVideoCallViewController *weakSelf = self;
   dispatch_async(dispatch_get_main_queue(), ^{
     ARDVideoCallViewController *strongSelf = weakSelf;