Fix animation glitch in blocking window.

Signal/src/util/OWSScreenLockUI.m

@@ -514,10 +514,6 @@ const UIWindowLevel UIWindowLevel_Background = -1.f;
 
     UIView *rootView = self.screenBlockingViewController.view;
 
-    [NSLayoutConstraint deactivateConstraints:self.screenBlockingConstraints];
-
-    NSMutableArray<NSLayoutConstraint *> *screenBlockingConstraints = [NSMutableArray new];
-
     BOOL shouldHaveScreenLock = desiredUIState == ScreenLockUIStateScreenLock;
     NSString *signature = [NSString stringWithFormat:@"%d %d", shouldHaveScreenLock, self.isShowingScreenLockUI];
     if ([NSObject isNullableObject:self.screenBlockingSignature equalTo:signature]) {
@@ -525,6 +521,10 @@ const UIWindowLevel UIWindowLevel_Background = -1.f;
         return;
     }
 
+    [NSLayoutConstraint deactivateConstraints:self.screenBlockingConstraints];
+
+    NSMutableArray<NSLayoutConstraint *> *screenBlockingConstraints = [NSMutableArray new];
+
     self.screenBlockingButton.hidden = !shouldHaveScreenLock;
 
     if (self.isShowingScreenLockUI) {

SignalMessaging/categories/UIView+OWS.h

@@ -118,6 +118,8 @@ CGFloat ScaleFromIPhone5(CGFloat iPhone5Value);
 - (void)addRedBorderRecursively;
 
 #ifdef DEBUG
+- (void)logFrame;
+- (void)logFrameWithLabel:(NSString *)label;
 - (void)logFrameLater;
 - (void)logFrameLaterWithLabel:(NSString *)label;
 - (void)logHierarchyUpwardLaterWithLabel:(NSString *)label;

SignalMessaging/categories/UIView+OWS.m

@@ -452,6 +452,21 @@ CGFloat ScaleFromIPhone5(CGFloat iPhone5Value)
     }
 }
 
+- (void)logFrame
+{
+    [self logFrameWithLabel:@""];
+}
+
+- (void)logFrameWithLabel:(NSString *)label
+{
+    DDLogVerbose(@"%@ %@ frame: %@, hidden: %d, opacity: %f",
+        self.logTag,
+        label,
+        NSStringFromCGRect(self.frame),
+        self.hidden,
+        self.layer.opacity);
+}
+
 - (void)logFrameLater
 {
     [self logFrameLaterWithLabel:@""];
@@ -460,12 +475,7 @@ CGFloat ScaleFromIPhone5(CGFloat iPhone5Value)
 - (void)logFrameLaterWithLabel:(NSString *)label
 {
     dispatch_async(dispatch_get_main_queue(), ^{
-        DDLogVerbose(@"%@ %@ frame: %@, hidden: %d, opacity: %f",
-            self.logTag,
-            label,
-            NSStringFromCGRect(self.frame),
-            self.hidden,
-            self.layer.opacity);
+        [self logFrameWithLabel:label];
     });
 }