Simplify TypingCommand::makeEditableRootEmpty() by removing firstElem…

…entChild

Simplify TypingCommand::makeEditableRootEmpty() by removing firstElementChild
https://bugs.webkit.org/show_bug.cgi?id=248191

Reviewed by Ryosuke Niwa.

Merge - https://src.chromium.org/viewvc/blink?view=revision&revision=180673

Simplify TypingCommand::makeEditableRootEmpty() a bit by avoiding an unnecessary
call to firstElementChild.

In this if scope, we already know that the root node has a single child.
Therefore, there is no reason to do a tree traversal, we can directly call
ContainerNode::firstChild().

firstElementChild never explores descendants and only looks
for the first direct child that is an Element. In this case, we don't need to
check if the child is an Element as we can pass a Node to hasTagName(brTag).

* Source/WebCore/editing/TypingCommand.cpp:
(TypingCommand::makeEditableRootEmpty): Simplify by removing references to firstElementChild

Canonical link: https://commits.webkit.org/256950@main

Source/WebCore/editing/TypingCommand.cpp

@@ -617,7 +617,7 @@ bool TypingCommand::makeEditableRootEmpty()
     if (!root || !root->firstChild())
         return false;
 
-    if (root->firstChild() == root->lastChild() && root->firstElementChild() && root->firstElementChild()->hasTagName(brTag)) {
+    if (root->firstChild() == root->lastChild() && root->firstChild()->hasTagName(brTag)) {
         // If there is a single child and it could be a placeholder, leave it alone.
         if (root->renderer() && root->renderer()->isRenderBlockFlow())
             return false;