GitLab

Merged the basic text selection functionality from the text_input_manager.js to text_navigation_manager.js. Also added variables to keep track of the start and end node for the selection and and added functionality to hide the set selection end button is the start of the selection is not set and show it as soon as the start is set.

Bug: 982004
Change-Id: I94b1e1dd3bf3636034276d0ee7db8c95a5711df1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1707036Reviewed-by: Anastasia Helfinstein <anastasi@google.com>
Commit-Queue: Rose Garcia <rosalindag@google.com>
Cr-Commit-Position: refs/heads/master@{#678935}