Update documentation and cleanup impls for localToSVGParentTransform()

Update documentation and cleanup impls for localToSVGParentTransform()

BUG=666416
Committed: https://crrev.com/478770fa0efff410715a804f55a4cc283a3a683e
Cr-Commit-Position: refs/heads/master@{#433344}

[Xianzhu, 2016-11-18 00:20:54]

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

[commit-bot: I haz the power, 2016-11-18 00:23:14]

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

[Xianzhu, 2016-11-18 00:47:38]

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

[commit-bot: I haz the power, 2016-11-18 00:49:26]

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

[Xianzhu, 2016-11-18 00:50:20]

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

[Xianzhu, 2016-11-18 00:50:21]

Hope this makes clear the concepts of "viewport-defining SVG object" and "local
SVG coordinates".

The next step is to make LayoutSVGText also a viewport-defining SVG object (by
moving some viewport related code from LayoutSVGForeignObject up into
LayoutSVGBlock), to fix the paint offset issue of LayoutSVGText. After that, all
non-root SVG objects will be painted with zero paint offsets.

[commit-bot: I haz the power, 2016-11-18 03:46:11]

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

[commit-bot: I haz the power, 2016-11-18 03:46:12]

Dry run: This issue passed the CQ dry run.

[pdr., 2016-11-18 20:35:10]

Much nicer!

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/LayoutObject.h (right):

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/LayoutObject.h:684: virtual
AffineTransform localSVGTransform() const;
Are there any remaining callsites of this after
https://crrev.com/74454dfeaa27a9f696824e0a2a1548175d2e26ab? I think it can be
removed entirely.

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceMarker.cpp
(right):

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceMarker.cpp:78: // If
this class were ever given a localTransform(), then the above would
Can you remove this comment?

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp (right):

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp:346: return
AffineTransform::translation(roundToInt(location().x()),
Wow, these m_localToParentTransform's were not even used.

I'm also a little skeptical of the old comment about optimizing the translation.

[Xianzhu, 2016-11-18 22:19:13]

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/LayoutObject.h (right):

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/LayoutObject.h:684: virtual
AffineTransform localSVGTransform() const;
On 2016/11/18 20:35:10, pdr. wrote:
> Are there any remaining callsites of this after
> https://crrev.com/74454dfeaa27a9f696824e0a2a1548175d2e26ab I think it can be
> removed entirely.

One callsite is in SVGLayoutTreeAsText which does need it.

The existence of localSVGTransform() also makes it easier to explain
localToSVGParentTransform().

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceMarker.cpp
(right):

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceMarker.cpp:78: // If
this class were ever given a localTransform(), then the above would
On 2016/11/18 20:35:10, pdr. wrote:
> Can you remove this comment?

Done.

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp (right):

https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp:346: return
AffineTransform::translation(roundToInt(location().x()),
On 2016/11/18 20:35:10, pdr. wrote:
> Wow, these m_localToParentTransform's were not even used.
> 
> I'm also a little skeptical of the old comment about optimizing the
translation.

They seemed to just to satisfy the previous returning type (const
AffineTransform&).

[pdr., 2016-11-18 22:20:37]

On 2016/11/18 at 22:19:13, wangxianzhu wrote:
>
https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/core/layout/LayoutObject.h (right):
> 
>
https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/layout/LayoutObject.h:684: virtual
AffineTransform localSVGTransform() const;
> On 2016/11/18 20:35:10, pdr. wrote:
> > Are there any remaining callsites of this after
> > https://crrev.com/74454dfeaa27a9f696824e0a2a1548175d2e26ab I think it can be
> > removed entirely.
> 
> One callsite is in SVGLayoutTreeAsText which does need it.
> 
> The existence of localSVGTransform() also makes it easier to explain
localToSVGParentTransform().
> 
>
https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceMarker.cpp
(right):
> 
>
https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/layout/svg/LayoutSVGResourceMarker.cpp:78: //
If this class were ever given a localTransform(), then the above would
> On 2016/11/18 20:35:10, pdr. wrote:
> > Can you remove this comment?
> 
> Done.
> 
>
https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
> File third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp (right):
> 
>
https://codereview.chromium.org/2514573003/diff/80001/third_party/WebKit/Sour...
> third_party/WebKit/Source/core/layout/svg/LayoutSVGRoot.cpp:346: return
AffineTransform::translation(roundToInt(location().x()),
> On 2016/11/18 20:35:10, pdr. wrote:
> > Wow, these m_localToParentTransform's were not even used.
> > 
> > I'm also a little skeptical of the old comment about optimizing the
translation.
> 
> They seemed to just to satisfy the previous returning type (const
AffineTransform&).

LGTM

[Xianzhu, 2016-11-18 22:32:09]

The CQ bit was checked by wangxianzhu@chromium.org

[commit-bot: I haz the power, 2016-11-18 22:32:59]

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, 2016-11-19 00:11:54]

Committed patchset #6 (id:100001)

[commit-bot: I haz the power, 2016-11-19 00:14:08]

Description was changed from

==========
Update documentation and cleanup impls for localToSVGParentTransform()

BUG=666416
==========

to

==========
Update documentation and cleanup impls for localToSVGParentTransform()

BUG=666416

Committed: https://crrev.com/478770fa0efff410715a804f55a4cc283a3a683e
Cr-Commit-Position: refs/heads/master@{#433344}
==========

[commit-bot: I haz the power, 2016-11-19 00:14:09]

Patchset 6 (id:??) landed as
https://crrev.com/478770fa0efff410715a804f55a4cc283a3a683e
Cr-Commit-Position: refs/heads/master@{#433344}