Factor out the <textPath> positioning mapping code into a helper class

Factor out the <textPath> positioning mapping code into a helper class

Since <textPath> will be getting a bunch of smaller new features - all
which essentially revolving around how the actual position is computed,
or how the actual path is setup, wrap the code that performs the
mapping from a location to a point on the path in a helper. The helper
is called PathPositionMapper, and for now resides with
LayoutSVGTextPath since that's the object that sets up the path data.

BUG=366559
Committed: https://crrev.com/5ce4904ba1d747f0d793f3a4abde842fd03853ab
Cr-Commit-Position: refs/heads/master@{#374893}

[fs, 2016-02-10 19:34:49]

fs@opera.com changed reviewers:
+ fmalita@chromium.org, pdr@chromium.org, schenney@chromium.org

[fs, 2016-02-10 19:34:50]

https://codereview.chromium.org/1683903004/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/layout/svg/LayoutSVGTextPath.h (right):

https://codereview.chromium.org/1683903004/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/svg/LayoutSVGTextPath.h:31: class
PathPositionMapper {
I guess this could go in platform/, but with this being the single user that
seemed like "premature layering". Let me know what you think.

[Stephen Chennney, 2016-02-10 19:49:05]

Do we have support for animation along path yet or something else needing point
and normal for length? If it doesn't exist yet, then I agree that leaving it
here for now is the right thing to do.

[fs, 2016-02-10 20:30:54]

On 2016/02/10 at 19:49:05, schenney wrote:
> Do we have support for animation along path yet or something else needing
point and normal for length? If it doesn't exist yet, then I agree that leaving
it here for now is the right thing to do.

We don't (yet?) have any other places that need to map a series of
samples/location like this does. We do have 'motion-path' and
SVGAnimateMotionElement though which only map a single sample/location. It's
possible that in the future they (or at least the former) would want to cache
something like this to exploit spatial locality.

[Stephen Chennney, 2016-02-10 21:18:14]

On 2016/02/10 20:30:54, fs wrote:
> On 2016/02/10 at 19:49:05, schenney wrote:
> > Do we have support for animation along path yet or something else needing
> point and normal for length? If it doesn't exist yet, then I agree that
leaving
> it here for now is the right thing to do.
> 
> We don't (yet?) have any other places that need to map a series of
> samples/location like this does. We do have 'motion-path' and
> SVGAnimateMotionElement though which only map a single sample/location. It's
> possible that in the future they (or at least the former) would want to cache
> something like this to exploit spatial locality.

Let's leave it here for now then. lgtm

[fs, 2016-02-11 14:00:24]

The CQ bit was checked by fs@opera.com

[fs, 2016-02-11 14:00:24]

The patchset sent to the CQ was uploaded after l-g-t-m from
schenney@chromium.org
Link to the patchset: https://codereview.chromium.org/1683903004/#ps20001
(title: "Rebase.")

[commit-bot: I haz the power, 2016-02-11 14:00:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1683903004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1683903004/20001

[commit-bot: I haz the power, 2016-02-11 14:05:26]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-02-16 22:35:29]

Description was changed from

==========
Factor out the <textPath> positioning mapping code into a helper class

Since <textPath> will be getting a bunch of smaller new features - all
which essentially revolving around how the actual position is computed,
or how the actual path is setup, wrap the code that performs the
mapping from a location to a point on the path in a helper. The helper
is called PathPositionMapper, and for now resides with
LayoutSVGTextPath since that's the object that sets up the path data.

BUG=366559
==========

to

==========
Factor out the <textPath> positioning mapping code into a helper class

Since <textPath> will be getting a bunch of smaller new features - all
which essentially revolving around how the actual position is computed,
or how the actual path is setup, wrap the code that performs the
mapping from a location to a point on the path in a helper. The helper
is called PathPositionMapper, and for now resides with
LayoutSVGTextPath since that's the object that sets up the path data.

BUG=366559

Committed: https://crrev.com/5ce4904ba1d747f0d793f3a4abde842fd03853ab
Cr-Commit-Position: refs/heads/master@{#374893}
==========

[commit-bot: I haz the power, 2016-02-16 22:35:30]

Patchset 2 (id:??) landed as
https://crrev.com/5ce4904ba1d747f0d793f3a4abde842fd03853ab
Cr-Commit-Position: refs/heads/master@{#374893}