dbus: add support for synchronous PropertySet::Get

dbus: add support for synchronous PropertySet::Get

The existing PropertySet::Get function is asynchronous.
This CL adds the synchronous version of PropertySet::Get.
It is defined as PropertySet::GetAndBlock.

Also fix some typos and indent problems in previous
introduced SetAndBlock().

BUG=https://b.corp.google.com/u/0/issues/24131409
TEST=manually tested

Committed: https://crrev.com/a5523d02410fc00401b569cfcac06f71b09b1c66
Cr-Commit-Position: refs/heads/master@{#351185}

[nywang, 2015-09-24 17:24:39]

nywang@chromium.org changed reviewers:
+ keybuk@chromium.org, pstew@chromium.org, zqiu@chromium.org

[nywang, 2015-09-28 20:18:15]

nywang@chromium.org changed reviewers:
+ satorux@chromium.org, stevenjb@chromium.org

[stevenjb, 2015-09-28 20:24:54]

https://codereview.chromium.org/1368713002/diff/20001/dbus/property.h
File dbus/property.h (right):

https://codereview.chromium.org/1368713002/diff/20001/dbus/property.h#newcode262
dbus/property.h:262: // The synchronous version of Get().
I assume this is for use outside of Chrome?

I would appreciate a warning that this should never be used on an interactive
thread, e.g. the chrome UI thread. (I realize that should be pretty obvious,
but... once upon a time blocking dbus calls were a huge source of jank on Chrome
OS).

https://codereview.chromium.org/1368713002/diff/20001/dbus/property.h#newcode285
dbus/property.h:285: // The synchronous version of Set().
We should add a warning here too.

[nywang, 2015-09-28 20:45:33]

https://codereview.chromium.org/1368713002/diff/20001/dbus/property.h
File dbus/property.h (right):

https://codereview.chromium.org/1368713002/diff/20001/dbus/property.h#newcode262
dbus/property.h:262: // The synchronous version of Get().
On 2015/09/28 20:24:54, stevenjb wrote:
> I assume this is for use outside of Chrome?
> 
> I would appreciate a warning that this should never be used on an interactive
> thread, e.g. the chrome UI thread. (I realize that should be pretty obvious,
> but... once upon a time blocking dbus calls were a huge source of jank on
Chrome
> OS).
> 

Thanks.

Yes this is used outside Chrome. It is for ChromeOS network manager (shill). We
need synchronous get/set to ensure events happen in an expected order.

I will add the warning here.

[stevenjb, 2015-09-28 21:30:45]

Thanks. LGTM

[nywang, 2015-09-28 21:37:33]

The CQ bit was checked by nywang@chromium.org

[commit-bot: I haz the power, 2015-09-28 21:38:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1368713002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1368713002/40001

[commit-bot: I haz the power, 2015-09-28 22:46:43]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-09-28 22:48:20]

Patchset 3 (id:??) landed as
https://crrev.com/a5523d02410fc00401b569cfcac06f71b09b1c66
Cr-Commit-Position: refs/heads/master@{#351185}