The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d

commit 18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d
Author: dimich <dimich@chromium.org>
Date: Tue Apr 26 19:15:07 2016

SnapshotController implementation. It will be used in WebContentsObservers for Offline Pages - to detect the right moment to make a snapshot.
It will take input and generate a sequence of StartSnapshot calls (typically 1 or 2) to its Client.
This is initial implementation, in the future we might update the logic to rely not on a timer and onload event,
but rather on some more specific indicators (meaningful layout or proportion of resources loaded).

BUG= 606106 

Review URL: https://codereview.chromium.org/1920603002

Cr-Commit-Position: refs/heads/master@{#389843}

[modify] https://crrev.com/18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d/components/components_tests.gyp
[modify] https://crrev.com/18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d/components/offline_pages.gypi
[modify] https://crrev.com/18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d/components/offline_pages/BUILD.gn
[add] https://crrev.com/18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d/components/offline_pages/snapshot_controller.cc
[add] https://crrev.com/18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d/components/offline_pages/snapshot_controller.h
[add] https://crrev.com/18a6b28cc90dfc6ecfeb075804a67f74e5c42f9d/components/offline_pages/snapshot_controller_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4410eaea5c56187d7a2d4c72694935245368ac29

commit 4410eaea5c56187d7a2d4c72694935245368ac29
Author: dimich <dimich@chromium.org>
Date: Thu May 05 00:01:35 2016

Implementing recent pages snapshot capture.
This adds functinoality to RecenttabHelper that:
- uses SnapshotController to detect when page should be captrued.
- uses simple algorithm to remove previous snapshot and limit number of current snapshots
- captures the page using MHTML Archiver and Offline Page Model.

Also has a couple of simple tests.

BUG= 606106 

Review-Url: https://codereview.chromium.org/1936613002
Cr-Commit-Position: refs/heads/master@{#391702}

[modify] https://crrev.com/4410eaea5c56187d7a2d4c72694935245368ac29/chrome/browser/android/offline_pages/recent_tab_helper.cc
[modify] https://crrev.com/4410eaea5c56187d7a2d4c72694935245368ac29/chrome/browser/android/offline_pages/recent_tab_helper.h
[modify] https://crrev.com/4410eaea5c56187d7a2d4c72694935245368ac29/chrome/browser/android/offline_pages/recent_tab_helper_unittest.cc
[modify] https://crrev.com/4410eaea5c56187d7a2d4c72694935245368ac29/components/offline_pages/snapshot_controller.cc
[modify] https://crrev.com/4410eaea5c56187d7a2d4c72694935245368ac29/components/offline_pages/snapshot_controller.h
[modify] https://crrev.com/4410eaea5c56187d7a2d4c72694935245368ac29/components/offline_pages/snapshot_controller_unittest.cc