Speedup sync chain creation time

[AlexeyBarabash]

Description

Current update interval for fetch records is 60 sec.
When sync chain is creating, device gets aware about it finished when it does fetch and sees other devices in chain. 60 seconds interval affects this phase so Device2 can appear in the list of devices of Device1 in 60 sec, which may seem too long.

Steps to Reproduce

1. On Device1 go to chrome://sync/
2. Press "Start new chain" => "Computer" => "Copy code"
3. On device 2 go to chrome://sync/
4. "Enter sync chain code" button
5. Paste the code
6. "Confirm sync code" button

Actual result:

Device1 gets created a sync chain much later (>15 sec) than Device2

Expected result:

Device1 gets created a sync chain not so late (<5 sec) after Device2

Reproduces how often:

Easily

Brave version (brave://version info)

Brave	0.60.4 Chromium: 72.0.3626.17 (Official Build) dev(64-bit)
Revision	08d2140079f8db14c9eb885a803d231b1a30e817-refs/branch-heads/3626@{#315}
OS	Linux

Reproducible on current release:

• Does it reproduce on brave-browser dev/beta builds?

[darkdh]

we also need to change fetch time when self delete/reset

[srirambv]

@AlexeyBarabash I see on Linux it takes 8secs as mentioned in #2782 (comment). Is this ok? The expected result says <5secs

[AlexeyBarabash]

@srirambv
I think, it is ok. I usually saw it almost rapidly after the PR, and ~1 minute before PR.
So 5 sec or 8 sec it seems the same order of time amount.

[srirambv]

Thanks for the confirmation @AlexeyBarabash . So anything below 10secs is a reasonable acceptable time I guess

Verification passed on

Brave	0.59.25 Chromium: 72.0.3626.53 (Official Build) beta(64-bit)
Revision	98434e6cd182d68ce396daa92e9c6310422e6763-refs/branch-heads/3626@{#620}
OS	Linux

Verification passed on

Brave	0.59.25 Chromium: 72.0.3626.53 (Official Build) beta (64-bit)
Revision	98434e6cd182d68ce396daa92e9c6310422e6763-refs/branch-heads/3626@{#620}
OS	Windows 10

• Verified STR from description. Device 1 took 6secs to create sync chain.

Verification PASSED on macOS 10.14.2 x64 using the following build:

Brave	0.59.28 Chromium: 72.0.3626.64 (Official Build) beta(64-bit)
Revision	eaa9668e80ce5405e7f1902579558ea725c06ca1-refs/branch-heads/3626@{#708}
OS	Mac OS X

• macOS 10.14.2 x64 --> Win 10 x64 - 3.5s (syncing my personal ~50 bookmarks)
• macOS 10.14.2 x64 --> Win 8.1 x74 - 4.3s (syncing my personal ~50 bookmarks)
• macOS 10.14.2 x64 --> Win 7 x74 - 4s (syncing my personal ~50 bookmarks)
• macOS 10.14.2 x64 --> Mint 19.1 x64 - 4.2s (syncing my personal ~50 bookmarks)