Fix for a long standing bug in Chrome windows with the auto hide taskbar.

Fix for a long standing bug in Chrome windows with the auto hide taskbar.

This bug reproduces at times with multiple monitors and occurs when our attempt to
retrieve the taskbar edge information via the ABM_GETAUTOHIDEBAR appbar message fails.
msdn recommends using the ABM_GETAUTOHIDEBAREX call with the monitor rectangle for the multiple
monitor case. However that does not work.

The following fallback does work though.
1. Query for the auto hide status of the taskbar.
2. Retrieve its position and check if the edge information returned in this call matches the
   edge we are looking for. This along with the monitor check is sufficient.

BUG=472139
TEST=Set taskbar to autohide. Connect multiple monitors to the machine and start chrome on the
primary monitor and attempt to reproduce this case. If it does not repro then move chrome to
the other monitor and attempt the test case. If that fails, disconnect the secondary monitor
exit chrome and try. One of these cases should reproduce the problem.

Committed: https://crrev.com/c64c903e110dc5f34a6348eb9b83e15900d96fbf
Cr-Commit-Position: refs/heads/master@{#361188}

[ananta, 2015-11-21 02:48:30]

ananta@chromium.org changed reviewers:
+ sky@chromium.org

[sky, 2015-11-22 15:57:19]

https://codereview.chromium.org/1462373003/diff/1/chrome/browser/ui/views/chr...
File chrome/browser/ui/views/chrome_views_delegate.cc (right):

https://codereview.chromium.org/1462373003/diff/1/chrome/browser/ui/views/chr...
chrome/browser/ui/views/chrome_views_delegate.cc:117: unsigned int taskbar_state
= SHAppBarMessage(ABM_GETSTATE,
All these ole function calls make me nervous that they're going to spin nested
message loops. What thread does this code urn on? Can we run it in the
background?

[ananta, 2015-11-23 19:10:44]

https://codereview.chromium.org/1462373003/diff/1/chrome/browser/ui/views/chr...
File chrome/browser/ui/views/chrome_views_delegate.cc (right):

https://codereview.chromium.org/1462373003/diff/1/chrome/browser/ui/views/chr...
chrome/browser/ui/views/chrome_views_delegate.cc:117: unsigned int taskbar_state
= SHAppBarMessage(ABM_GETSTATE,
On 2015/11/22 15:57:19, sky wrote:
> All these ole function calls make me nervous that they're going to spin nested
> message loops. What thread does this code urn on? Can we run it in the
> background?

Please see below. The function GetAppbarAutohideEdgesOnWorkerThread which calls
this function runs in a worker thread. If memory serves me right, you did this.
:)

[sky, 2015-11-23 19:15:28]

:) LGTM

[ananta, 2015-11-23 19:51:21]

The CQ bit was checked by ananta@chromium.org

[commit-bot: I haz the power, 2015-11-23 19:53:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1462373003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1462373003/1

[commit-bot: I haz the power, 2015-11-23 21:28:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-23 21:29:11]

Patchset 1 (id:??) landed as
https://crrev.com/c64c903e110dc5f34a6348eb9b83e15900d96fbf
Cr-Commit-Position: refs/heads/master@{#361188}