Fix blurry content after disabling dev tools emulation

Fix blurry content after disabling dev tools emulation

There's a race between page resize and devtools emulation disabling
which can change the root layer transform scale.  If a commit occurs
after the page resize but before the scale, then layers end up picking
the wrong scale, and if they have will-change on them then they will
not change again after the root layer transform scale.

This scale isn't really part of the page or under the author's control,
and so will-change should be ignored when devtools changes the scale
and content should always be rerastered and the ideal scale.

This patch implements that behavior by plumbing a flag all the way from
the devtools scale change to LayerTreeHost which then then resets the
raster scale on all the picture layers after commit.

BUG=630979
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Committed: https://crrev.com/8a4cb786c49505784365acdb1ca4037df64b341f
Cr-Commit-Position: refs/heads/master@{#422914}

[enne (OOO), 2016-10-03 23:24:06]

Description was changed from

==========
Fix blurry content after disabling dev tools emulation

There's a race between page resize and devtools emulation disabling
which can change the root layer transform scale.  If a commit occurs
after the page resize but before the scale, then layers end up picking
the wrong scale, and if they have will-change on them then they will
not change again after the root layer transform scale.

This scale isn't really part of the page or under the author's control,
and so will-change should be ignored when devtools changes the scale
and content should always be rerastered and the ideal scale.

This patch implements that behavior by plumbing a flag all the way from
the devtools scale change to LayerTreeHost which then then resets the
raster scale on all the picture layers after commit.

BUG=630979
==========

to

==========
Fix blurry content after disabling dev tools emulation

There's a race between page resize and devtools emulation disabling
which can change the root layer transform scale.  If a commit occurs
after the page resize but before the scale, then layers end up picking
the wrong scale, and if they have will-change on them then they will
not change again after the root layer transform scale.

This scale isn't really part of the page or under the author's control,
and so will-change should be ignored when devtools changes the scale
and content should always be rerastered and the ideal scale.

This patch implements that behavior by plumbing a flag all the way from
the devtools scale change to LayerTreeHost which then then resets the
raster scale on all the picture layers after commit.

BUG=630979
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

[enne (OOO), 2016-10-03 23:27:25]

enne@chromium.org changed reviewers:
+ vmpstr@chromium.org

[enne (OOO), 2016-10-03 23:27:30]

wdyt?

https://codereview.chromium.org/2390923002/diff/1/third_party/WebKit/Source/w...
File third_party/WebKit/Source/web/WebViewImpl.cpp (right):

https://codereview.chromium.org/2390923002/diff/1/third_party/WebKit/Source/w...
third_party/WebKit/Source/web/WebViewImpl.cpp:4580: void
WebViewImpl::updateDeviceEmulationTransform() {
Renamed this as devtools is the only consumer of this function so that I could
put the recalculate raster scale call inside of here.

[vmpstr, 2016-10-04 00:25:53]

Thanks for looking into this. I think the plumbing and the new functionality
makes sense. It's nice to have a switch to force crisp content. lgtm.

https://codereview.chromium.org/2390923002/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/web/WebViewImpl.cpp (right):

https://codereview.chromium.org/2390923002/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/web/WebViewImpl.cpp:4589:
m_layerTreeView->forceRecalculateRasterScales();
I wonder if this is going to cause inconsistencies in real pages that have
will-change transform and they change the transform so the content is blurry.
Then changing the device type will reset it so that the content is crisp. I
think this is OK. WDYT?

[enne (OOO), 2016-10-04 16:47:59]

enne@chromium.org changed reviewers:
+ pdr@chromium.org

[enne (OOO), 2016-10-04 16:48:44]

enne@chromium.org changed reviewers:
+ chrishtr@chromium.org

[enne (OOO), 2016-10-04 16:49:21]

+pdr for Blink Source/web and public/platform
+chrishtr FYI for some nuance on dealing with will-change: transform scale
changes

https://codereview.chromium.org/2390923002/diff/40001/third_party/WebKit/Sour...
File third_party/WebKit/Source/web/WebViewImpl.cpp (right):

https://codereview.chromium.org/2390923002/diff/40001/third_party/WebKit/Sour...
third_party/WebKit/Source/web/WebViewImpl.cpp:4589:
m_layerTreeView->forceRecalculateRasterScales();
On 2016/10/04 at 00:25:53, vmpstr wrote:
> I wonder if this is going to cause inconsistencies in real pages that have
will-change transform and they change the transform so the content is blurry.
Then changing the device type will reset it so that the content is crisp. I
think this is OK. WDYT?

Yeah, I also think it is ok to crisp up content here that would have been
blurry.  I think disabling device emulation is an operation that we can jank on
and do a layout / paint / reraster.  Nobody is expecting that operation to run
at 60hz imo.

[enne (OOO), 2016-10-04 16:49:25]

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

[commit-bot: I haz the power, 2016-10-04 16:49:47]

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, 2016-10-04 17:04:42]

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

[commit-bot: I haz the power, 2016-10-04 17:04:42]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[enne (OOO), 2016-10-04 18:17:11]

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

[commit-bot: I haz the power, 2016-10-04 18:17:47]

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

[pdr., 2016-10-04 20:19:10]

On 2016/10/04 at 16:49:21, enne wrote:
> +pdr for Blink Source/web and public/platform
LGTM

[commit-bot: I haz the power, 2016-10-04 20:24:23]

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

[commit-bot: I haz the power, 2016-10-04 20:24:24]

Dry run: This issue passed the CQ dry run.

[enne (OOO), 2016-10-04 20:28:02]

The CQ bit was checked by enne@chromium.org

[enne (OOO), 2016-10-04 20:28:02]

The patchset sent to the CQ was uploaded after l-g-t-m from vmpstr@chromium.org
Link to the patchset: https://codereview.chromium.org/2390923002/#ps60001
(title: "Add function for LayerTreeHostRemote")

[commit-bot: I haz the power, 2016-10-04 20:28:55]

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, 2016-10-04 20:37:16]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-10-04 20:41:32]

Description was changed from

==========
Fix blurry content after disabling dev tools emulation

There's a race between page resize and devtools emulation disabling
which can change the root layer transform scale.  If a commit occurs
after the page resize but before the scale, then layers end up picking
the wrong scale, and if they have will-change on them then they will
not change again after the root layer transform scale.

This scale isn't really part of the page or under the author's control,
and so will-change should be ignored when devtools changes the scale
and content should always be rerastered and the ideal scale.

This patch implements that behavior by plumbing a flag all the way from
the devtools scale change to LayerTreeHost which then then resets the
raster scale on all the picture layers after commit.

BUG=630979
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
==========

to

==========
Fix blurry content after disabling dev tools emulation

There's a race between page resize and devtools emulation disabling
which can change the root layer transform scale.  If a commit occurs
after the page resize but before the scale, then layers end up picking
the wrong scale, and if they have will-change on them then they will
not change again after the root layer transform scale.

This scale isn't really part of the page or under the author's control,
and so will-change should be ignored when devtools changes the scale
and content should always be rerastered and the ideal scale.

This patch implements that behavior by plumbing a flag all the way from
the devtools scale change to LayerTreeHost which then then resets the
raster scale on all the picture layers after commit.

BUG=630979
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Committed: https://crrev.com/8a4cb786c49505784365acdb1ca4037df64b341f
Cr-Commit-Position: refs/heads/master@{#422914}
==========

[commit-bot: I haz the power, 2016-10-04 20:41:33]

Patchset 4 (id:??) landed as
https://crrev.com/8a4cb786c49505784365acdb1ca4037df64b341f
Cr-Commit-Position: refs/heads/master@{#422914}