Resizing call banner window

problem is the navigation bar is now too tall, since it has room for
status.

We could shirnk the nav bar, but maybe it's easier to just have the call
banner in the navbar?

// FREEBIE

Signal/src/util/OWSWindowManager.m

@@ -156,6 +156,13 @@ const UIWindowLevel UIWindowLevel_ScreenBlocking(void)
     label.font = [UIFont ows_regularFontWithSize:14.f];
     [rootView addSubview:label];
 
+    [label autoPinBottomToSuperviewMargin];
+    [label setCompressionResistanceHigh];
+    [label setContentHuggingHigh];
+    [label autoHCenterInSuperview];
+
+    // TODO animate...
+
     // returnToCallLabel uses manual layout.
     //
     // TODO: Is there a better way to do this?
@@ -329,21 +336,21 @@ const UIWindowLevel UIWindowLevel_ScreenBlocking(void)
     } else if (self.callViewController) {
         // Show Root Window + "Return to Call".
 
-        [self ensureRootWindowShown];
+        [self ensureRootWindowShownWithActiveCall:YES];
         [self ensureReturnToCallWindowShown];
         [self ensureCallViewWindowHidden];
         [self ensureScreenBlockWindowHidden];
     } else {
         // Show Root Window
 
-        [self ensureRootWindowShown];
+        [self ensureRootWindowShownWithActiveCall:NO];
         [self ensureReturnToCallWindowHidden];
         [self ensureCallViewWindowHidden];
         [self ensureScreenBlockWindowHidden];
     }
 }
 
-- (void)ensureRootWindowShown
+- (void)ensureRootWindowShownWithActiveCall:(BOOL)isActiveCall
 {
     OWSAssertIsOnMainThread();
 
@@ -351,11 +358,27 @@ const UIWindowLevel UIWindowLevel_ScreenBlocking(void)
         DDLogInfo(@"%@ showing root window.", self.logTag);
     }
 
+    static CGRect defaultFrame;
+    static CGRect frameWithActiveCall;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        defaultFrame = self.rootWindow.frame;
+
+        CGFloat callBannerHeight = self.returnToCallWindow.frame.size.height;
+        frameWithActiveCall
+            = CGRectMake(0, callBannerHeight, defaultFrame.size.width, defaultFrame.size.height - callBannerHeight);
+    });
+
+    if (isActiveCall) {
+        self.rootWindow.frame = frameWithActiveCall;
+    } else {
+        self.rootWindow.frame = defaultFrame;
+    }
+
     // By calling makeKeyAndVisible we ensure the rootViewController becomes firt responder.
     // In the normal case, that means the SignalViewController will call `becomeFirstResponder`
     // on the vc on top of its navigation stack.
     [self.rootWindow makeKeyAndVisible];
-
 }
 
 - (void)ensureRootWindowHidden