Sequential focus navigation staring point: Fix a case where clicked Text node has focusable siblings.

In the following case:
  <div>
    <input>
    text
    <input>
  <div>
If the "text" is clicked, we wrongly record its parent elemnt as sequential
focus navigation starting point. We should record the Text node as is.

BUG=454172
TEST=automated

Review URL: https://codereview.chromium.org/1738603002

Cr-Commit-Position: refs/heads/master@{#377499}
2 files changed