Add TOS-accepted Java pref on Android.

Add TOS-accepted Java pref on Android.

This will support being able to show the first page of the
FRE without native code being initialized yet, so that we
could fetch a variations seed while it's showing, which I'm
working on under crbug.com/632199

This change adds a Java-level pref for TOS-accepted, so it
can be checked before native is initialized. Also makes the
code sync the existing native pref to the Java pref for users
migrating from old versions. (We may want to merge this CL
back ahead of the main FRE de-nativization work so that users
can migrate their prefs ahead of time.)

BUG=668741
Review-Url: https://codereview.chromium.org/2531743003
Cr-Commit-Position: refs/heads/master@{#435283}
(cherry picked from commit 03e06cc174fe2cbba5fab1291442e470e5e94b09)

Review-Url: https://codereview.chromium.org/2623643002 .
Cr-Commit-Position: refs/branch-heads/2924@{#705}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}
Committed: https://chromium.googlesource.com/chromium/src/+/e4fc556210b701b9da0c446212f753c707723655

[Alexei Svitkine (slow), 2017-01-09 20:23:22]

Description was changed from

==========
Add TOS-accepted Java pref on Android.

This will support being able to show the first page of the
FRE without native code being initialized yet, so that we
could fetch a variations seed while it's showing, which I'm
working on under crbug.com/632199

This change adds a Java-level pref for TOS-accepted, so it
can be checked before native is initialized. Also makes the
code sync the existing native pref to the Java pref for users
migrating from old versions. (We may want to merge this CL
back ahead of the main FRE de-nativization work so that users
can migrate their prefs ahead of time.)

BUG=668741

Review-Url: https://codereview.chromium.org/2531743003
Cr-Commit-Position: refs/heads/master@{#435283}
(cherry picked from commit 03e06cc174fe2cbba5fab1291442e470e5e94b09)
==========

to

==========
Add TOS-accepted Java pref on Android.

This will support being able to show the first page of the
FRE without native code being initialized yet, so that we
could fetch a variations seed while it's showing, which I'm
working on under crbug.com/632199

This change adds a Java-level pref for TOS-accepted, so it
can be checked before native is initialized. Also makes the
code sync the existing native pref to the Java pref for users
migrating from old versions. (We may want to merge this CL
back ahead of the main FRE de-nativization work so that users
can migrate their prefs ahead of time.)

BUG=668741

Review-Url: https://codereview.chromium.org/2531743003
Cr-Commit-Position: refs/heads/master@{#435283}
(cherry picked from commit 03e06cc174fe2cbba5fab1291442e470e5e94b09)

Review-Url: https://codereview.chromium.org/2623643002 .
Cr-Commit-Position: refs/branch-heads/2924@{#705}
Cr-Branched-From:
3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}
Committed:
https://chromium.googlesource.com/chromium/src/+/e4fc556210b701b9da0c446212f7...
==========

[Alexei Svitkine (slow), 2017-01-09 20:23:24]

Committed patchset #1 (id:1) manually as
e4fc556210b701b9da0c446212f753c707723655.