Fix video slow to appear on first launch.

BUG=webrtc:7777

Review-Url: https://codereview.webrtc.org/3006453002
Cr-Commit-Position: refs/heads/master@{#19497}
diff --git a/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m b/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m
index 6e3dbb5..9237484 100644
--- a/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m
+++ b/webrtc/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m
@@ -141,8 +141,8 @@
                       }
                       [self reconfigureCaptureSessionInput];
                       [self updateOrientation];
-                      [_captureSession startRunning];
                       [self updateDeviceCaptureFormat:format fps:fps];
+                      [_captureSession startRunning];
                       [_currentDevice unlockForConfiguration];
                       _isRunning = YES;
                     }];