arc: Do not keep track of in-flight decode requests.

arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() as needed (e.g. on destruction).

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.

Committed: https://crrev.com/f4f0263355892832547b5449aa50e41fa118b7c3
Cr-Commit-Position: refs/heads/master@{#407728}

[Shuhei Takahashi, 2016-07-25 06:18:41]

nya@chromium.org changed reviewers:
+ hidehiko@chromium.org

[Shuhei Takahashi, 2016-07-25 06:18:42]

hidehiko: PTAL

[Shuhei Takahashi, 2016-07-25 06:18:56]

The CQ bit was checked by nya@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-25 06:19:09]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-25 06:19:10]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-25 06:19:11]

Dry run: No L-G-T-M from a valid reviewer yet. 
CQ run can only be started by full committers or once the patch has
received an L-G-T-M from a full committer.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[hidehiko, 2016-07-25 19:17:20]

The code LGTM, but I'd like to hear your design opinion.

https://codereview.chromium.org/2175213002/diff/1/chrome/browser/chromeos/arc...
File chrome/browser/chromeos/arc/arc_wallpaper_handler.cc (right):

https://codereview.chromium.org/2175213002/diff/1/chrome/browser/chromeos/arc...
chrome/browser/chromeos/arc/arc_wallpaper_handler.cc:63: class
ArcWallpaperHandler::ImageRequestImpl
Optional: Now this class looks not having any important roll?
Can this be merged into enclosing class?
WDYT?

https://codereview.chromium.org/2175213002/diff/1/chrome/browser/chromeos/arc...
chrome/browser/chromeos/arc/arc_wallpaper_handler.cc:114: if
(inflight_request_.get()) {
DCHECK_CURRENTLY_ON(UI); here, too?

[Shuhei Takahashi, 2016-07-26 05:40:12]

Description was changed from

==========
arc: Keep track of at most one in-flight wallpaper request.

When a wallpaper request is made while another request is
in-flight, we can cancel the in-flight request immediately.

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

to

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be used in
multiple decode requests, we don't need to keep track of in-flight
requests. We just need to call ImageDecoder::Cancel() on destruction.

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

[Shuhei Takahashi, 2016-07-26 05:41:43]

hidehiko: PTAL

Thanks for comments. Could you take another look as I made some non-trivial
changes?

https://codereview.chromium.org/2175213002/diff/1/chrome/browser/chromeos/arc...
File chrome/browser/chromeos/arc/arc_wallpaper_handler.cc (right):

https://codereview.chromium.org/2175213002/diff/1/chrome/browser/chromeos/arc...
chrome/browser/chromeos/arc/arc_wallpaper_handler.cc:63: class
ArcWallpaperHandler::ImageRequestImpl
On 2016/07/25 19:17:20, hidehiko wrote:
> Optional: Now this class looks not having any important roll?
> Can this be merged into enclosing class?
> WDYT?

Thanks, now I can implement ImageRequest in ArcWallpaperHandler.

https://codereview.chromium.org/2175213002/diff/1/chrome/browser/chromeos/arc...
chrome/browser/chromeos/arc/arc_wallpaper_handler.cc:114: if
(inflight_request_.get()) {
On 2016/07/25 19:17:20, hidehiko wrote:
> DCHECK_CURRENTLY_ON(UI); here, too?

This function was removed.

[hidehiko, 2016-07-26 06:19:10]

https://codereview.chromium.org/2175213002/diff/10001/chrome/browser/chromeos...
File chrome/browser/chromeos/arc/arc_wallpaper_handler.cc (right):

https://codereview.chromium.org/2175213002/diff/10001/chrome/browser/chromeos...
chrome/browser/chromeos/arc/arc_wallpaper_handler.cc:71: // TODO(nya): Improve
ImageDecoder to minimize copy.
As we chatted offline, to make the behavior slightly predictable, could you add
Cancel(this) here?

[Shuhei Takahashi, 2016-07-26 06:22:07]

https://codereview.chromium.org/2175213002/diff/10001/chrome/browser/chromeos...
File chrome/browser/chromeos/arc/arc_wallpaper_handler.cc (right):

https://codereview.chromium.org/2175213002/diff/10001/chrome/browser/chromeos...
chrome/browser/chromeos/arc/arc_wallpaper_handler.cc:71: // TODO(nya): Improve
ImageDecoder to minimize copy.
On 2016/07/26 06:19:10, hidehiko wrote:
> As we chatted offline, to make the behavior slightly predictable, could you
add
> Cancel(this) here?

Done.

[Shuhei Takahashi, 2016-07-26 06:24:18]

The CQ bit was checked by nya@chromium.org

[Shuhei Takahashi, 2016-07-26 06:24:18]

The patchset sent to the CQ was uploaded after l-g-t-m from
hidehiko@chromium.org
Link to the patchset: https://codereview.chromium.org/2175213002/#ps30001
(title: ".")

[commit-bot: I haz the power, 2016-07-26 06:24:28]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Shuhei Takahashi, 2016-07-26 06:25:10]

The CQ bit was unchecked by nya@chromium.org

[Shuhei Takahashi, 2016-07-26 06:26:17]

Description was changed from

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be used in
multiple decode requests, we don't need to keep track of in-flight
requests. We just need to call ImageDecoder::Cancel() on destruction.

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

to

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() on destruction.

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

[Shuhei Takahashi, 2016-07-26 06:26:42]

Description was changed from

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() on destruction.

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

to

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() as needed (e.g. on destruction).

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

[Shuhei Takahashi, 2016-07-26 06:26:58]

The CQ bit was checked by nya@chromium.org

[commit-bot: I haz the power, 2016-07-26 06:27:10]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-26 07:06:53]

Description was changed from

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() as needed (e.g. on destruction).

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

to

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() as needed (e.g. on destruction).

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

[commit-bot: I haz the power, 2016-07-26 07:06:54]

Committed patchset #3 (id:30001)

[commit-bot: I haz the power, 2016-07-26 07:09:27]

Description was changed from

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() as needed (e.g. on destruction).

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.
==========

to

==========
arc: Do not keep track of in-flight decode requests.

Since ImageDecoder allows the same ImageRequest to be reused,
ArcWallpaperHandler can implement ImageRequest. We just need to
call ImageDecoder::Cancel() as needed (e.g. on destruction).

BUG=None
TEST=Tested setting wallpaper manually with ARC enabled device.

Committed: https://crrev.com/f4f0263355892832547b5449aa50e41fa118b7c3
Cr-Commit-Position: refs/heads/master@{#407728}
==========

[commit-bot: I haz the power, 2016-07-26 07:09:28]

Patchset 3 (id:??) landed as
https://crrev.com/f4f0263355892832547b5449aa50e41fa118b7c3
Cr-Commit-Position: refs/heads/master@{#407728}