Use dark scrollbar theme for transparent frames.

Use dark scrollbar theme for transparent frames.

If the given background color is totally transparent we should default
to using the dark theme since that's the default. ChromeOS OOBE pages,
for example, set an override background color of "TRANSPARENT" which is
#00000000 in RGBA. Our old logic looked only at the RGB bits so it
concluded that the frame had a black background and used white scollbars.

We don't have enough information in Blink to know what theme to use in
this case but falling back to the default theme should be good enough.

BUG=709978
Review-Url: https://codereview.chromium.org/2840223002
Cr-Commit-Position: refs/heads/master@{#467382}
Committed: https://chromium.googlesource.com/chromium/src/+/f82b1ff2761897b38ae79042810fb0a9f3ff747f

[bokan, 2017-04-26 15:12:06]

Description was changed from

==========
Use dark scrollbar theme for transparent frames.

If the given background color is totally transparent we should default
to using the dark theme since that's the default. ChromeOS OOBE pages,
for example, set an override background color of "TRANSPARENT" which is
the frame had a black background so it used white scrollbars.

BUG=709978
==========

to

==========
Use dark scrollbar theme for transparent frames.

If the given background color is totally transparent we should default
to using the dark theme since that's the default. ChromeOS OOBE pages,
for example, set an override background color of "TRANSPARENT" which is
#00000000 in RGBA so our old logic concluded the frame had a black
background so it used white scrollbars.

BUG=709978
==========

[bokan, 2017-04-26 15:12:07]

bokan@chromium.org changed reviewers:
+ skobes@chromium.org

[bokan, 2017-04-26 15:13:57]

Description was changed from

==========
Use dark scrollbar theme for transparent frames.

If the given background color is totally transparent we should default
to using the dark theme since that's the default. ChromeOS OOBE pages,
for example, set an override background color of "TRANSPARENT" which is
#00000000 in RGBA so our old logic concluded the frame had a black
background so it used white scrollbars.

BUG=709978
==========

to

==========
Use dark scrollbar theme for transparent frames.

If the given background color is totally transparent we should default
to using the dark theme since that's the default. ChromeOS OOBE pages,
for example, set an override background color of "TRANSPARENT" which is
#00000000 in RGBA. Our old logic looked only at the RGB bits so it
concluded that the frame had a black background and used white scollbars.

We don't have enough information in Blink to know what theme to use in
this case but falling back to the default theme should be good enough.

BUG=709978
==========

[bokan, 2017-04-26 15:58:06]

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

[commit-bot: I haz the power, 2017-04-26 15:58:29]

Dry run: CQ is trying da patch.

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

[skobes, 2017-04-26 15:58:49]

lgtm

[commit-bot: I haz the power, 2017-04-26 18:05:16]

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

[commit-bot: I haz the power, 2017-04-26 18:05:17]

Dry run: This issue passed the CQ dry run.

[bokan, 2017-04-26 18:08:09]

bokan@chromium.org changed reviewers:
+ jbroman@chromium.org

[bokan, 2017-04-26 18:08:19]

+jbroman@ for platform

[jbroman, 2017-04-26 18:10:20]

lgtm

https://codereview.chromium.org/2840223002/diff/1/third_party/WebKit/Source/p...
File third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp (right):

https://codereview.chromium.org/2840223002/diff/1/third_party/WebKit/Source/p...
third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp:439: if (lightness
<= .5 && background_color.Alpha())
Possibly the ideal threshold is a little higher than 1/255, but I'm fine with
whatever.

[bokan, 2017-04-26 18:11:58]

https://codereview.chromium.org/2840223002/diff/1/third_party/WebKit/Source/p...
File third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp (right):

https://codereview.chromium.org/2840223002/diff/1/third_party/WebKit/Source/p...
third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp:439: if (lightness
<= .5 && background_color.Alpha())
On 2017/04/26 18:10:20, jbroman wrote:
> Possibly the ideal threshold is a little higher than 1/255, but I'm fine with
> whatever.

Yeah, I thought about that but the scrollbar theme is already mostly a wild
guess so this is just a fix to a common occurrence. We'll adjust if it comes up.

[bokan, 2017-04-26 18:12:05]

The CQ bit was checked by bokan@chromium.org

[commit-bot: I haz the power, 2017-04-26 18:12:27]

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, 2017-04-26 18:17:07]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493230325152050, "parent_rev":
"d35ed4510ac666f199cc280c9eec8400cb8b9f03", "commit_rev":
"f82b1ff2761897b38ae79042810fb0a9f3ff747f"}

[commit-bot: I haz the power, 2017-04-26 18:18:19]

Description was changed from

==========
Use dark scrollbar theme for transparent frames.

If the given background color is totally transparent we should default
to using the dark theme since that's the default. ChromeOS OOBE pages,
for example, set an override background color of "TRANSPARENT" which is
#00000000 in RGBA. Our old logic looked only at the RGB bits so it
concluded that the frame had a black background and used white scollbars.

We don't have enough information in Blink to know what theme to use in
this case but falling back to the default theme should be good enough.

BUG=709978
==========

to

==========
Use dark scrollbar theme for transparent frames.

If the given background color is totally transparent we should default
to using the dark theme since that's the default. ChromeOS OOBE pages,
for example, set an override background color of "TRANSPARENT" which is
#00000000 in RGBA. Our old logic looked only at the RGB bits so it
concluded that the frame had a black background and used white scollbars.

We don't have enough information in Blink to know what theme to use in
this case but falling back to the default theme should be good enough.

BUG=709978

Review-Url: https://codereview.chromium.org/2840223002
Cr-Commit-Position: refs/heads/master@{#467382}
Committed:
https://chromium.googlesource.com/chromium/src/+/f82b1ff2761897b38ae79042810f...
==========

[commit-bot: I haz the power, 2017-04-26 18:18:20]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/f82b1ff2761897b38ae79042810f...