Fix iOS8 crash in background mode.

webrtc/sdk/objc/Framework/Classes/RTCAVFoundationVideoCapturerInternal.mm

 /*
  *  Copyright 2016 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 "RTCAVFoundationVideoCapturerInternal.h"
 
 #import <Foundation/Foundation.h>
 #if TARGET_OS_IPHONE
 #import <UIKit/UIKit.h>
+#import "WebRTC/UIDevice+RTCDevice.h"
 #endif
 
 #import "RTCDispatcher+Private.h"
 #import "WebRTC/RTCLogging.h"
 
 #include "avfoundationformatmapper.h"
 
 @implementation RTCAVFoundationVideoCapturerInternal {
   // Keep pointers to inputs for convenience.
   AVCaptureDeviceInput *_frontCameraInput;
@@ skipping 199 matching lines @@
          fromConnection:(AVCaptureConnection *)connection {
   RTCLogError(@"Dropped sample buffer.");
 }
 
 #pragma mark - AVCaptureSession notifications
 
 - (void)handleCaptureSessionInterruption:(NSNotification *)notification {
   NSString *reasonString = nil;
 #if defined(__IPHONE_9_0) && defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && \
     __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_9_0
-  NSNumber *reason = notification.userInfo[AVCaptureSessionInterruptionReasonKey];
-  if (reason) {
-    switch (reason.intValue) {
-      case AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableInBackground:
-        reasonString = @"VideoDeviceNotAvailableInBackground";
-        break;
-      case AVCaptureSessionInterruptionReasonAudioDeviceInUseByAnotherClient:
-        reasonString = @"AudioDeviceInUseByAnotherClient";
-        break;
-      case AVCaptureSessionInterruptionReasonVideoDeviceInUseByAnotherClient:
-        reasonString = @"VideoDeviceInUseByAnotherClient";
-        break;
-      case AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableWithMultipleForegroundApps:
-        reasonString = @"VideoDeviceNotAvailableWithMultipleForegroundApps";
-        break;
+  if ([UIDevice isIOS9OrLater]) {
+    NSNumber *reason = notification.userInfo[AVCaptureSessionInterruptionReasonKey];
+    if (reason) {
+      switch (reason.intValue) {
+        case AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableInBackground:
+          reasonString = @"VideoDeviceNotAvailableInBackground";
+          break;
+        case AVCaptureSessionInterruptionReasonAudioDeviceInUseByAnotherClient:
+          reasonString = @"AudioDeviceInUseByAnotherClient";
+          break;
+        case AVCaptureSessionInterruptionReasonVideoDeviceInUseByAnotherClient:
+          reasonString = @"VideoDeviceInUseByAnotherClient";
+          break;
+        case AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableWithMultipleForegroundApps:
+          reasonString = @"VideoDeviceNotAvailableWithMultipleForegroundApps";
+          break;
+      }
     }
   }
 #endif
   RTCLog(@"Capture session interrupted: %@", reasonString);
   // TODO(tkchin): Handle this case.
 }
 
 - (void)handleCaptureSessionInterruptionEnded:(NSNotification *)notification {
   RTCLog(@"Capture session interruption ended.");
   // TODO(tkchin): Handle this case.
@@ skipping 231 matching lines @@
                                    AVCaptureDevice *newDevice = newInput.device;
                                    const cricket::VideoFormat *format =
                                      _capturer->GetCaptureFormat();
                                    webrtc::SetFormatForCaptureDevice(
                                        newDevice, _captureSession, *format);
                                    [_captureSession commitConfiguration];
                                }];
 }
 
 @end