Fix renderer assert after autofill

PasswordAutofillAgent may modify value of newFocusedNode in BlurEvent
dispatched above, while newFocusedNode->isFocusable() expects that
newFocusedNode->needsLayout() not to be true, updateLayout() here in
case that happens.

BUG=251163

Review URL: https://chromiumcodereview.appspot.com/21346002

git-svn-id: svn://svn.chromium.org/blink/trunk@158348 bbb929c8-8fbe-4397-9dbb-9b2b20218538