[iOS][MF] Return when the keyboard is not found

Bug: 918522
Change-Id: I125e8d3477fa52b980b8d38a65a5a2360da425b7
Reviewed-on: https://chromium-review.googlesource.com/c/1461677Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630597}

ios/chrome/browser/autofill/form_input_accessory_view_controller.mm

@@ -411,6 +411,9 @@ CGFloat const kInputAccessoryHeight = 44.0f;
     if (IsIPadIdiom()) {
       // On iPad the keyboard view can change so this updates it when needed.
       UIView* keyboardView = [self getKeyboardView];
+      if (!keyboardView) {
+        return;
+      }
       if (self.inputAccessoryView.superview) {
         if (keyboardView == self.inputAccessoryView.superview) {
           return;