GitLab

Show paste option on right click of bookmark bar if some URL is copied from outside browser or from any page content

Paste option was not appearing when some URL is copied from outside browser
or web page content. But if some URL is copied from url bar the paste option
appears when right click is performed on bookmark bar. Added check in
CanPasteFromClipboard to handle this scenario.

BUG=400644

Review URL: https://codereview.chromium.org/437423005

Cr-Commit-Position: refs/heads/master@{#294380}