Add salient_image_url to ContentSuggestion

This is populated for RemoteSuggestions.
The plan is to use this in offline_pages/ to fetch the suggested image URL,
instead of relying on ntp_snippets to fetch the URL.

Bug: 841522
Change-Id: I18ad866ec3b6ad39509df50421eef51a7a976380
Reviewed-by: Carlos Knippschild <>
Reviewed-by: Filip Gorski <>
Commit-Queue: Dan H <>
Cr-Commit-Position: refs/heads/master@{#578368}
4 files changed