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- save a workspace in window's property.
- trigger saving to browser session when property is updated, but
need force saving in `WindowOpened()` for newly created window.
- restore each window to the right desk by assigning to the right
parent desk container in `GetDefaultParentForWindow()`.
- resolve desk activation conflict between browser session and
an active desk restore by checking `IsSessionRestoreInProgress()`
in ash to avoid every single window activation during restore.
- resolve the parent desk conflict between the first restored window
and a blank window by stop reusing the blank window for restore
and always create a new window during restoration.
- resolve clobbering tab restore by passing null browser when using
desks restore feature.
- add browser tests checking that each window restore to the parent
desk if DesksRestore enabled, otherwise to the first desk, which is a
default active desk after a crash.

`browser_tests --gtest_filter=*SessionRestoreTestChromeOS*`

Bug: 996999
Test: Manual test (a video in crbug comment 27) and browser tests
Change-Id: I0f9202e10a7b861a676725e7390b15fd71a00933
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2572316
Commit-Queue: Cattalyya Nuengsigkapian <cattalyya@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840778}