Handle correctly start and commit of non-latest navigations.

Handle correctly start and commit of non-latest navigations.

Notable changes:
 - didStartProvisionalNavigation: is no op if passed navigation is not the latest
    navigation (this way didStartProvisionalNavigation: does not mess up with
    pending item)
 - didCommitNavigation: does not commit pending entry if if passed navigation
    is not the latest navigation. Instead it changes last committed item to one
    that matches with URL, which may not be correct, but it's just a minor
    temporary inconsistency which does not have any security implications
    (last committed URL is still correct).

BUG=711465
Review-Url: https://codereview.chromium.org/2821173002
Cr-Commit-Position: refs/heads/master@{#465669}
(cherry picked from commit 79d9b86732316df528fbfe72409465e9bf2668b1)

Review-Url: https://codereview.chromium.org/2832853002 .
Cr-Commit-Position: refs/branch-heads/3071@{#84}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/1e54e3f192007513ef53ba2f48d7dc8641636dbf

[Eugene But (OOO till 7-30), 2017-04-20 16:11:00]

Description was changed from

==========
Handle correctly start and commit of non-latest navigations.

Notable changes:
 - didStartProvisionalNavigation: is no op if passed navigation is not the
latest
    navigation (this way didStartProvisionalNavigation: does not mess up with
    pending item)
 - didCommitNavigation: does not commit pending entry if if passed navigation
    is not the latest navigation. Instead it changes last committed item to one
    that matches with URL, which may not be correct, but it's just a minor
    temporary inconsistency which does not have any security implications
    (last committed URL is still correct).

BUG=711465

Review-Url: https://codereview.chromium.org/2821173002
Cr-Commit-Position: refs/heads/master@{#465669}
(cherry picked from commit 79d9b86732316df528fbfe72409465e9bf2668b1)
==========

to

==========
Handle correctly start and commit of non-latest navigations.

Notable changes:
 - didStartProvisionalNavigation: is no op if passed navigation is not the
latest
    navigation (this way didStartProvisionalNavigation: does not mess up with
    pending item)
 - didCommitNavigation: does not commit pending entry if if passed navigation
    is not the latest navigation. Instead it changes last committed item to one
    that matches with URL, which may not be correct, but it's just a minor
    temporary inconsistency which does not have any security implications
    (last committed URL is still correct).

BUG=711465

Review-Url: https://codereview.chromium.org/2821173002
Cr-Commit-Position: refs/heads/master@{#465669}
(cherry picked from commit 79d9b86732316df528fbfe72409465e9bf2668b1)

Review-Url: https://codereview.chromium.org/2832853002 .
Cr-Commit-Position: refs/branch-heads/3071@{#84}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/1e54e3f192007513ef53ba2f48d7...
==========

[Eugene But (OOO till 7-30), 2017-04-20 16:11:02]

Committed patchset #1 (id:1) manually as
1e54e3f192007513ef53ba2f48d7dc8641636dbf (tree was closed).