Restart capture session if needed on active.

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

 /*
  *  Copyright 2015 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.
  */
 
@@ skipping 96 matching lines @@
                    name:UIDeviceOrientationDidChangeNotification
                  object:nil];
     [center addObserver:self
                selector:@selector(handleCaptureSessionInterruption:)
                    name:AVCaptureSessionWasInterruptedNotification
                  object:_captureSession];
     [center addObserver:self
                selector:@selector(handleCaptureSessionInterruptionEnded:)
                    name:AVCaptureSessionInterruptionEndedNotification
                  object:_captureSession];
+    [center addObserver:self
+               selector:@selector(handleApplicationDidBecomeActive:)
+                   name:UIApplicationDidBecomeActiveNotification
+                 object:[UIApplication sharedApplication]];
 #endif
     [center addObserver:self
                selector:@selector(handleCaptureSessionRuntimeError:)
                    name:AVCaptureSessionRuntimeErrorNotification
                  object:_captureSession];
     [center addObserver:self
                selector:@selector(handleCaptureSessionDidStartRunning:)
                    name:AVCaptureSessionDidStartRunningNotification
                  object:_captureSession];
     [center addObserver:self
@@ skipping 217 matching lines @@
 - (void)handleNonFatalError {
   [RTCDispatcher dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
                                block:^{
     if (self.hasStarted) {
       RTCLog(@"Restarting capture session after error.");
       [self.captureSession startRunning];
     }
   }];
 }
 
+#if TARGET_OS_IPHONE
+
+#pragma mark - UIApplication notifications
+
+- (void)handleApplicationDidBecomeActive:(NSNotification *)notification {
+  [RTCDispatcher dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
+                               block:^{
+    if (self.hasStarted && !self.captureSession.isRunning) {
+      RTCLog(@"Restarting capture session on active.");
+      [self.captureSession startRunning];
+    }
+  }];
+}
+
+#endif  // TARGET_OS_IPHONE
+
 #pragma mark - Private
 
 - (BOOL)setupCaptureSession {
   AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
 #if defined(__IPHONE_7_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_7_0
   NSString *version = [[UIDevice currentDevice] systemVersion];
   if ([version integerValue] >= 7) {
     captureSession.usesApplicationAudioSession = NO;
   }
 #endif
@@ skipping 361 matching lines @@
   }
 
   OnFrame(cricket::WebRtcVideoFrame(buffer, webrtc::kVideoRotation_0,
                                     translated_camera_time_us, 0),
           captured_width, captured_height);
 
   CVBufferRelease(image_buffer);
 }
 
 }  // namespace webrtc