[DIAL] Break circular dependency in DialFetchDeviceDescriptionFunction.

[DIAL] Break circular dependency in DialFetchDeviceDescriptionFunction.

DeviceDescriptionFetcher has 2 references (in the 2 calbacks) to the
DialFetchDeviceDescriptionFunction that owns it, but only 1 of the 2
references is removed at the end state. This results in a circular
dependency which prevents the function from being destroyed. This patch
manually destroys the DeviceDescriptionFetcher after the fetching is
done to break the circular dependency.

BUG=688089
Review-Url: https://codereview.chromium.org/2668383004
Cr-Commit-Position: refs/heads/master@{#447857}
(cherry picked from commit d8033dadec98c7c2f4c407f89c128b166b5922ef)

Review-Url: https://codereview.chromium.org/2674573011 .
Cr-Commit-Position: refs/branch-heads/2987@{#304}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed: https://chromium.googlesource.com/chromium/src/+/b656c780b62f5bca1465324360c2be28ee73deca

[imcheng, 2017-02-03 22:48:39]

Description was changed from

==========
[DIAL] Break circular dependency in DialFetchDeviceDescriptionFunction.

DeviceDescriptionFetcher has 2 references (in the 2 calbacks) to the
DialFetchDeviceDescriptionFunction that owns it, but only 1 of the 2
references is removed at the end state. This results in a circular
dependency which prevents the function from being destroyed. This patch
manually destroys the DeviceDescriptionFetcher after the fetching is
done to break the circular dependency.

BUG=688089

Review-Url: https://codereview.chromium.org/2668383004
Cr-Commit-Position: refs/heads/master@{#447857}
(cherry picked from commit d8033dadec98c7c2f4c407f89c128b166b5922ef)
==========

to

==========
[DIAL] Break circular dependency in DialFetchDeviceDescriptionFunction.

DeviceDescriptionFetcher has 2 references (in the 2 calbacks) to the
DialFetchDeviceDescriptionFunction that owns it, but only 1 of the 2
references is removed at the end state. This results in a circular
dependency which prevents the function from being destroyed. This patch
manually destroys the DeviceDescriptionFetcher after the fetching is
done to break the circular dependency.

BUG=688089

Review-Url: https://codereview.chromium.org/2668383004
Cr-Commit-Position: refs/heads/master@{#447857}
(cherry picked from commit d8033dadec98c7c2f4c407f89c128b166b5922ef)

Review-Url: https://codereview.chromium.org/2674573011 .
Cr-Commit-Position: refs/branch-heads/2987@{#304}
Cr-Branched-From:
ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}
Committed:
https://chromium.googlesource.com/chromium/src/+/b656c780b62f5bca1465324360c2...
==========

[imcheng, 2017-02-03 22:48:42]

Committed patchset #1 (id:1) manually as
b656c780b62f5bca1465324360c2be28ee73deca.