Don't ask for camera permissions if app is not active.

// FREEBIE

Signal/src/Signal-Bridging-Header.h

@@ -39,6 +39,7 @@
 #import "UIImage+OWS.h"
 #import "UIUtil.h"
 #import "UIView+OWS.h"
+#import "UIViewController+CameraPermissions.h"
 #import "ViewControllerUtils.h"
 #import <AxolotlKit/NSData+keyVersionByte.h>
 #import <Foundation/Foundation.h>

Signal/src/call/CallService.swift

@@ -1103,33 +1103,34 @@ protocol CallServiceObserver: class {
     func setHasLocalVideo(hasLocalVideo: Bool) {
         AssertIsOnMainThread()
 
-        let authStatus = AVCaptureDevice.authorizationStatus(forMediaType:AVMediaTypeVideo)
-        switch authStatus {
-        case .notDetermined:
-            Logger.debug("\(TAG) authStatus: AVAuthorizationStatusNotDetermined")
-            break
-        case .restricted:
-            Logger.debug("\(TAG) authStatus: AVAuthorizationStatusRestricted")
-            break
-        case .denied:
-            Logger.debug("\(TAG) authStatus: AVAuthorizationStatusDenied")
-            break
-        case .authorized:
-            Logger.debug("\(TAG) authStatus: AVAuthorizationStatusAuthorized")
-            break
+        guard let frontmostViewController = UIApplication.shared.frontmostViewController else {
+            owsFail("\(TAG) could not identify frontmostViewController in \(#function)")
+            return
         }
 
+        frontmostViewController.ows_ask(forCameraPermissions: { [weak self] in
+            // Success callback; camera permissions are granted.
+
+            guard let strongSelf = self else {
+                return
+            }
+
+            strongSelf.setHasLocalVideoWithCameraPermissions(hasLocalVideo: hasLocalVideo)
+
+            }, failureCallback: {
+                // Failed callback; camera permissions are _NOT_ granted.
+
                 // We don't need to worry about the user granting or remoting this permission
                 // during a call while the app is in the background, because changing this
                 // permission kills the app.
-        if authStatus != .authorized {
-
                 OWSAlerts.showAlert(withTitle: NSLocalizedString("MISSING_CAMERA_PERMISSION_TITLE", comment: "Alert title when camera is not authorized"),
                                     message: NSLocalizedString("MISSING_CAMERA_PERMISSION_MESSAGE", comment: "Alert body when camera is not authorized"))
-
-            return
+        })
     }
 
+    private func setHasLocalVideoWithCameraPermissions(hasLocalVideo: Bool) {
+        AssertIsOnMainThread()
+
         guard let call = self.call else {
             // This should never happen; return to a known good state.
             owsFail("\(TAG) call was unexpectedly nil in \(#function)")
@@ -1434,7 +1435,7 @@ protocol CallServiceObserver: class {
         AssertIsOnMainThread()
 
         if case CallError.assertionError(description: let description) = error {
-            owsFail(description)
+            Logger.error(description)
         }
 
         if let failedCall = failedCall {

Signal/src/util/UIViewController+CameraPermissions.m

@@ -19,12 +19,20 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)ows_askForCameraPermissions:(void (^)(void))permissionsGrantedCallback
                     failureCallback:(nullable void (^)(void))failureCallback
 {
+    DDLogVerbose(@"%@ ows_askForCameraPermissions", NSStringFromClass(self.class));
+
     // Avoid nil tests below.
     if (!failureCallback) {
         failureCallback = ^{
         };
     }
 
+    if ([UIApplication sharedApplication].applicationState != UIApplicationStateActive) {
+        DDLogError(@"Skipping camera permissions request when app is not active.");
+        failureCallback();
+        return;
+    }
+
     if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
         DDLogError(@"Camera ImagePicker source not available");
         failureCallback();