Make vw/vh units to work in css transforms.

Make vw/vh units to work in css transforms.

RenderView object isn't available to calculate viewport size when the transforms
are expanding the percentage to real size. Pass the RenderView object to
the Transform object's apply() and blend() functions accordingly. And also
to Graphics layer and RenderStyle objects for addAnimation and applyTransforms.

BUG=137617

[Srini, 2013-08-16 20:35:59]

Can you review this patch? I would be happy to fix any issues needs to be fixed
in this.

NB: Sorry, the code change small but is across 38 files and the names I saw on
git blame weren't owners around the code. So I just went by the git cl 's
suggestion for OWNERS. Please suggest me if you aren't the right OWNDER to
review. Thanks!

[Srini, 2013-08-16 20:40:02]

This patch fixes the bug it advertises, but I guess it also fixes some other
bugs that are around viewport (vw/vh) units, as I went ahead and made changes
that were needed due to RenderView being passed across various objects.

[adamk, 2013-08-16 21:27:34]

Kent & I are definitely not the best reviewers for this code; hopefully jamesr
will either be a good reviewer or will who know else to ask.

[Srini, 2013-08-17 15:23:10]

jamesr: Can you look at this patch? Thanks!

[jamesr, 2013-08-19 03:19:49]

https://codereview.chromium.org/22900008/diff/1/Source/core/platform/graphics...
File Source/core/platform/graphics/GraphicsLayer.h (right):

https://codereview.chromium.org/22900008/diff/1/Source/core/platform/graphics...
Source/core/platform/graphics/GraphicsLayer.h:66: class RenderView;
No.  RenderView is a core/rendering/ concept and code in core/platform/ should
not depend on anything in core/ that's not in platform/.

[jamesr, 2013-08-19 03:21:08]

Viewport size changes are rare relative to things changing in the page.  Can't
we just resolve viewport units to absolute values whenever the viewport changes
instead of passing the viewport around everywhere?

[jamesr, 2013-08-19 03:22:39]

I.e. exactly what was proposed here for gecko:
https://bugzilla.mozilla.org/show_bug.cgi?id=503720#c17

[Srini, 2013-08-19 07:39:10]

On 2013/08/19 03:22:39, jamesr wrote:
> I.e. exactly what was proposed here for gecko:
> https://bugzilla.mozilla.org/show_bug.cgi?id=503720#c17

I'll check this up. Thanks for the review jamesr

[Srini, 2013-08-19 19:32:00]

On 2013/08/19 07:39:10, Srini wrote:
> On 2013/08/19 03:22:39, jamesr wrote:
> > I.e. exactly what was proposed here for gecko:
> > https://bugzilla.mozilla.org/show_bug.cgi?id=503720#c17
> 
> I'll check this up. Thanks for the review jamesr

jamesr: IIUC you want the v* units to be calculated after parsed, calculated
with the current viewport size and stored. When the viewport size changes, some
listener with some callback to re-calc the values. I have been fixing few
viewports issues and almost all of them were due to the fact that
floatValueForLength has null renderView. If we can do this, it fixes blanket of
viewport related bugs from size, position to transforms, etc. I would certainly
start in this direction, I would definitely look for your help as Im just new to
this. To begin with, I'll see if I can calculate and store the values as
Fixed/Number type and then see how I will recalc the entire tree on viewport
changes. Does the approach seems fine or can you suggest better approaches?
Thanks.

[Srini, 2013-08-20 20:25:59]

On 2013/08/19 19:32:00, Srini wrote:
> On 2013/08/19 07:39:10, Srini wrote:
> > On 2013/08/19 03:22:39, jamesr wrote:
> > > I.e. exactly what was proposed here for gecko:
> > > https://bugzilla.mozilla.org/show_bug.cgi?id=503720#c17
> > 
> > I'll check this up. Thanks for the review jamesr
> 
> jamesr: IIUC you want the v* units to be calculated after parsed, calculated
> with the current viewport size and stored. When the viewport size changes,
some
> listener with some callback to re-calc the values. I have been fixing few
> viewports issues and almost all of them were due to the fact that
> floatValueForLength has null renderView. If we can do this, it fixes blanket
of
> viewport related bugs from size, position to transforms, etc. I would
certainly
> start in this direction, I would definitely look for your help as Im just new
to
> this. To begin with, I'll see if I can calculate and store the values as
> Fixed/Number type and then see how I will recalc the entire tree on viewport
> changes. Does the approach seems fine or can you suggest better approaches?
> Thanks.

jamesr: I have been reading the code of how I could do. I probably don't have
the complete picture. Can I do something like use CSSValuePool and cache the
computed value. Im also stuck with how to see that this gets updated when the
viewport changes. Any thoughts/suggestions? I even thought if I could just pass
ViewportSize all along, but then that doesn't appear clean. I'm stuck a bit and
appreciate any directions. Thanks!

[jamesr, 2013-08-20 20:26:37]

Please file a bug or start a discussion on blink-dev@ about how to do this. 
Code reviews aren't the best place for design discussions.

[Srini, 2013-08-20 20:35:04]

On 2013/08/20 20:26:37, jamesr wrote:
> Please file a bug or start a discussion on blink-dev@ about how to do this. 
> Code reviews aren't the best place for design discussions.

I'll start a thread on blink-dev. Thanks jamesr

[jamesr, 2013-08-20 20:40:40]

Sounds great.  Thanks for looking into this!

[Srini, 2013-08-20 20:45:52]

On 2013/08/20 20:40:40, jamesr wrote:
> Sounds great.  Thanks for looking into this!

Anytime! (btw, I just started an email discussion on blink-dev)

[Srini, 2013-09-17 11:18:45]

On 2013/08/20 20:45:52, Srini wrote:
> On 2013/08/20 20:40:40, jamesr wrote:
> > Sounds great.  Thanks for looking into this!
> 
> Anytime! (btw, I just started an email discussion on blink-dev)

Jamesr: tabatkins suggested to keep the implementation of viewports similar to
the percentage implementation. Logically it makes sense. Except that on the code
level, it makes easier for Percent because, it is mostly the immediate
containing block where as the viewport is percent of size of initial containing
block. Getting the size of ICB is my problem now. Also  the ICB size is now
calculated (from ScrollView) with consideration of scrollbar etc, which
tabatkins said doesn't make sense after the spec changes. So I think I have come
with two things to do to solve this:

1) Modify the way we compute the size of the viewport (may be from
m_fixedlayoutsize ?)
2) Have this information in a more accessible class that could be accessed from
various places without breaking the abstraction. (like RenderView in platform
etc)

I would need some suggestions if this the right way to go and if so, could you
suggest some more information on how I go about the above approach. If Im
totally wrong, feel free to correct me, I would go about the right direction.

Thanks,
-Srini.

[jamesr, 2013-09-18 00:57:08]

Please take this discussion to blink-dev - there are many people who are
probably equipped than me to give you feedback on the design and code reviews
are awkward places to have in-depth discussions.