Correct the activation of idle time spell checker on document attach

Correct the activation of idle time spell checker on document attach

There is a bug that, when a document is attached, the idle time spell
checker is requested for cold mode invocation even without the
IdleTimeSpellChecking flag.

This patch fixes the bug. To ensure that idle time spell checker is
only invoked with the flag, a DCHECK is also added to the handleEvnet()
function.

Related unit tests are disabled when there is no flag.

BUG=700081, 517298, 706329
Review-Url: https://codereview.chromium.org/2744603004
Cr-Commit-Position: refs/heads/master@{#455942}
(cherry picked from commit 624c5cfae4ce865f8ac91be865a29ff0e9fdbe34)

Review-Url: https://codereview.chromium.org/2790763002 .
Cr-Commit-Position: refs/branch-heads/3029@{#499}
Cr-Branched-From: 939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed: https://chromium.googlesource.com/chromium/src/+/29a3cd8a8d8a0b9cdc72cde72d38cf7bd9a7d25b

[Xiaocheng, 2017-03-30 21:16:55]

Description was changed from

==========
Correct the activation of idle time spell checker on document attach

There is a bug that, when a document is attached, the idle time spell
checker is requested for cold mode invocation even without the
IdleTimeSpellChecking flag.

This patch fixes the bug. To ensure that idle time spell checker is
only invoked with the flag, a DCHECK is also added to the handleEvnet()
function.

Related unit tests are disabled when there is no flag.

BUG=700081,517298,706329

Review-Url: https://codereview.chromium.org/2744603004
Cr-Commit-Position: refs/heads/master@{#455942}
(cherry picked from commit 624c5cfae4ce865f8ac91be865a29ff0e9fdbe34)
==========

to

==========
Correct the activation of idle time spell checker on document attach

There is a bug that, when a document is attached, the idle time spell
checker is requested for cold mode invocation even without the
IdleTimeSpellChecking flag.

This patch fixes the bug. To ensure that idle time spell checker is
only invoked with the flag, a DCHECK is also added to the handleEvnet()
function.

Related unit tests are disabled when there is no flag.

BUG=700081,517298,706329

Review-Url: https://codereview.chromium.org/2744603004
Cr-Commit-Position: refs/heads/master@{#455942}
(cherry picked from commit 624c5cfae4ce865f8ac91be865a29ff0e9fdbe34)

Review-Url: https://codereview.chromium.org/2790763002 .
Cr-Commit-Position: refs/branch-heads/3029@{#499}
Cr-Branched-From:
939b32ee5ba05c396eef3fd992822fcca9a2e262-refs/heads/master@{#454471}
Committed:
https://chromium.googlesource.com/chromium/src/+/29a3cd8a8d8a0b9cdc72cde72d38...
==========

[Xiaocheng, 2017-03-30 21:16:56]

Committed patchset #1 (id:1) manually as
29a3cd8a8d8a0b9cdc72cde72d38cf7bd9a7d25b.