[Content suggestions] Never update snippets after FetchMore

[Content suggestions] Never update snippets after FetchMore

The new logic for replacing snippets does not work well for the case
after more suggestions are fetched by the provider on demand and
appended to the list.

This CL switches off replacing the snippets after any snippets have been
appended.

BUG=683050
Review-Url: https://codereview.chromium.org/2644143003
Cr-Commit-Position: refs/heads/master@{#446005}
(cherry picked from commit 389bba160bee7a83f0fd3b0227b6757dc8ae3e77)

Review-Url: https://codereview.chromium.org/2656323002 .
Cr-Commit-Position: refs/branch-heads/2987@{#139}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed: https://chromium.googlesource.com/chromium/src/+/948a7f73e91c84ef7bf4f9921887a39a11fbb20f

[jkrcal, 2017-01-27 09:49:40]

Description was changed from

==========
[Content suggestions] Never update snippets after FetchMore

The new logic for replacing snippets does not work well for the case
after more suggestions are fetched by the provider on demand and
appended to the list.

This CL switches off replacing the snippets after any snippets have been
appended.

BUG=683050

Review-Url: https://codereview.chromium.org/2644143003
Cr-Commit-Position: refs/heads/master@{#446005}
(cherry picked from commit 389bba160bee7a83f0fd3b0227b6757dc8ae3e77)
==========

to

==========
[Content suggestions] Never update snippets after FetchMore

The new logic for replacing snippets does not work well for the case
after more suggestions are fetched by the provider on demand and
appended to the list.

This CL switches off replacing the snippets after any snippets have been
appended.

BUG=683050

Review-Url: https://codereview.chromium.org/2644143003
Cr-Commit-Position: refs/heads/master@{#446005}
(cherry picked from commit 389bba160bee7a83f0fd3b0227b6757dc8ae3e77)

Review-Url: https://codereview.chromium.org/2656323002 .
Cr-Commit-Position: refs/branch-heads/2987@{#139}
Cr-Branched-From:
ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed:
https://chromium.googlesource.com/chromium/src/+/948a7f73e91c84ef7bf4f9921887...
==========

[jkrcal, 2017-01-27 09:49:41]

Committed patchset #1 (id:1) manually as
948a7f73e91c84ef7bf4f9921887a39a11fbb20f.