Use JumpList icon caches to remove redundant favicon loading

This CL applies the icon caches to save unnecessary favicon loading from
the FaviconService. The icon caches have already been used to trim out
the redundant icon creation and deletion on disk as in crrev/2859193005.
These two changes make the best of the icon caches.

BUG=40407, 717236

Review-Url: https://codereview.chromium.org/2936053002
Cr-Commit-Position: refs/heads/master@{#480122}
1 file changed