Use inherited statusbar height (rather than hardcoded 20px) so height…

… on correct on iPhone X family

src/ios/CDVInAppBrowser.m

@@ -32,7 +32,6 @@ Licensed to the Apache Software Foundation (ASF) under one
 #define    IAB_BRIDGE_NAME @"cordova_iab"
 
 #define    TOOLBAR_HEIGHT 44.0
-#define    STATUSBAR_HEIGHT 20.0
 #define    LOCATIONBAR_HEIGHT 21.0
 #define    FOOTER_HEIGHT ((TOOLBAR_HEIGHT) + (LOCATIONBAR_HEIGHT))
 
@@ -962,8 +961,12 @@ - (void)viewWillAppear:(BOOL)animated
     if (IsAtLeastiOSVersion(@"7.0") && !viewRenderedAtLeastOnce) {
         viewRenderedAtLeastOnce = TRUE;
         CGRect viewBounds = [self.webView bounds];
-        viewBounds.origin.y = STATUSBAR_HEIGHT;
-        viewBounds.size.height = viewBounds.size.height - STATUSBAR_HEIGHT;
+
+        CGRect statusBarFrame = [UIApplication sharedApplication].statusBarFrame;
+        CGFloat statusBarHeight = statusBarFrame.size.height;
+
+        viewBounds.origin.y = statusBarHeight;
+        viewBounds.size.height = viewBounds.size.height - statusBarHeight;
         self.webView.frame = viewBounds;
         [[UIApplication sharedApplication] setStatusBarStyle:[self preferredStatusBarStyle]];
     }
@@ -1220,9 +1223,6 @@ - (void) dismissViewControllerAnimated:(BOOL)flag completion:(void (^)(void))com
 - (void) viewDidLoad {
 
     CGRect statusBarFrame = [self invertFrameIfNeeded:[UIApplication sharedApplication].statusBarFrame];
-    statusBarFrame.size.height = STATUSBAR_HEIGHT;
-    // simplified from: http://stackoverflow.com/a/25669695/219684
-
     UIToolbar* bgToolbar = [[UIToolbar alloc] initWithFrame:statusBarFrame];
     bgToolbar.barStyle = UIBarStyleDefault;
     [bgToolbar setAutoresizingMask:UIViewAutoresizingFlexibleWidth];