Rewrite SVG text-decoration handling to not require GC scale-adjustment

Rewrite SVG text-decoration handling to not require GC scale-adjustment

Since drawing decorations for text means drawing "regular geometry" rather
than specially-scaled glyphs of a font, there's no need to first append
the inverse scale-factor the CTM and then scale the geometry - just adjust
the computed (scaled) font-metrics and emit unscaled geometry.
This allows for the stroke thickness adjustment to only be applied in the
text-case, so sink it out of PaintingResourceScope.
Also modify the function that computes the offset for the decorations to
do so relative to the baseline, and rename it accordingly.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182615

[fs, 2014-09-24 13:27:46]

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

[Stephen Chennney, 2014-09-24 14:56:53]

lgtm with minor comment fix.

https://codereview.chromium.org/601763002/diff/1/Source/core/rendering/svg/SV...
File Source/core/rendering/svg/SVGInlineTextBox.cpp (right):

https://codereview.chromium.org/601763002/diff/1/Source/core/rendering/svg/SV...
Source/core/rendering/svg/SVGInlineTextBox.cpp:461: // Compatible with
Batik/Opera.
Nit, we compatible with Opera by default. Maybe "old Opera" or whatever you guys
call the pre-Blink version.

[fs, 2014-09-24 15:54:04]

https://codereview.chromium.org/601763002/diff/1/Source/core/rendering/svg/SV...
File Source/core/rendering/svg/SVGInlineTextBox.cpp (right):

https://codereview.chromium.org/601763002/diff/1/Source/core/rendering/svg/SV...
Source/core/rendering/svg/SVGInlineTextBox.cpp:461: // Compatible with
Batik/Opera.
On 2014/09/24 14:56:52, Stephen Chenney wrote:
> Nit, we compatible with Opera by default. Maybe "old Opera" or whatever you
guys
> call the pre-Blink version.

Hehe, yeah, this has been problematic for us too... ("Opera, uhm... Presto!").
I'll just change it to Presto-Opera or maybe just Presto.

[fs, 2014-09-24 16:01:44]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2014-09-24 16:02:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/601763002/20001

[commit-bot: I haz the power, 2014-09-24 17:04:39]

Committed patchset #2 (id:20001) as 182615