Don't load a splash screen by default (#6883)

shell/platform/darwin/ios/framework/Headers/FlutterViewController.h

@@ -88,7 +88,7 @@ FLUTTER_EXPORT
  *
  * @param asset The name of the asset. The name can be hierarchical.
  * @param package The name of the package from which the asset originates.
- * @returns: The file name to be used for lookup in the main bundle.
+ * @return The file name to be used for lookup in the main bundle.
  */
 - (NSString*)lookupKeyForAsset:(NSString*)asset fromPackage:(NSString*)package;
 
@@ -129,15 +129,19 @@ FLUTTER_EXPORT
  * a replacement until the first frame is rendered.
  *
  * The view used should be appropriate for multiple sizes; an autoresizing mask to
- * have a flexible
- * width and height will be applied automatically.
- *
- * If not specified, uses a view generated from `UILaunchStoryboardName` from the
- * main bundle's
- * `Info.plist` file.
+ * have a flexible width and height will be applied automatically.
  */
 @property(strong, nonatomic) UIView* splashScreenView;
 
+/**
+ * Attempts to set the `splashScreenView` property from the `UILaunchStoryboardName` from the
+ * main bundle's `Info.plist` file.  This method will not change the value of `splashScreenView`
+ * if it cannot find a default one from a storyboard or nib.
+ *
+ * @return `YES` if successful, `NO` otherwise.
+ */
+- (BOOL)loadDefaultSplashScreenView;
+
 /**
  * Controls whether the created view will be opaque or not.
  *

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -239,7 +239,7 @@
 - (void)installSplashScreenViewIfNecessary {
   // Show the launch screen view again on top of the FlutterView if available.
   // This launch screen view will be removed once the first Flutter frame is rendered.
-  if (self.isBeingPresented || self.isMovingToParentViewController) {
+  if (_splashScreenView && (self.isBeingPresented || self.isMovingToParentViewController)) {
     [_splashScreenView.get() removeFromSuperview];
     _splashScreenView.reset();
     return;
@@ -305,21 +305,29 @@
 }
 
 - (UIView*)splashScreenView {
-  if (_splashScreenView == nullptr) {
-    NSString* launchscreenName =
-        [[[NSBundle mainBundle] infoDictionary] objectForKey:@"UILaunchStoryboardName"];
-    if (launchscreenName == nil) {
-      return nil;
-    }
-    UIView* splashView = [self splashScreenFromStoryboard:launchscreenName];
-    if (!splashView) {
-      splashView = [self splashScreenFromXib:launchscreenName];
-    }
-    self.splashScreenView = splashView;
+  if (!_splashScreenView) {
+    return nil;
   }
   return _splashScreenView.get();
 }
 
+- (BOOL)loadDefaultSplashScreenView {
+  NSString* launchscreenName =
+      [[[NSBundle mainBundle] infoDictionary] objectForKey:@"UILaunchStoryboardName"];
+  if (launchscreenName == nil) {
+    return NO;
+  }
+  UIView* splashView = [self splashScreenFromStoryboard:launchscreenName];
+  if (!splashView) {
+    splashView = [self splashScreenFromXib:launchscreenName];
+  }
+  if (!splashView) {
+    return NO;
+  }
+  self.splashScreenView = splashView;
+  return YES;
+}
+
 - (UIView*)splashScreenFromStoryboard:(NSString*)name {
   UIStoryboard* storyboard = nil;
   @try {
@@ -347,16 +355,10 @@
   if (!view) {
     // Special case: user wants to remove the splash screen view.
     [self removeSplashScreenViewIfPresent];
-  } else if (_splashScreenView) {
-    FML_LOG(ERROR) << "Attempt to set the FlutterViewController's splash screen multiple times was "
-                      "ignored. The FlutterViewController's splash screen can only be set once. "
-                      "This condition can occur if a running FlutterEngine instance has been "
-                      "passed into the FlutterViewController and a consumer later called "
-                      "[FlutterViewController setSplashScreen:]. Setting the splash screen on a "
-                      "FlutterViewController with an already running engine is not supported, as "
-                      "the rasterizer will already be running by the time the view is shown.";
+    _splashScreenView.reset();
     return;
   }
+
   _splashScreenView.reset([view retain]);
   _splashScreenView.get().autoresizingMask =
       UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;