Store a <scale, bias> tuple for textLength scale adjustment

Store a <scale, bias> tuple for textLength scale adjustment

SVGTextFragment::lengthAdjustTransform only ever has two values that
could make it differ from the identity transform.
By storing only these two values - and as floats rather than doubles -
instead of the full AffineTransform, the size of SVGTextFragment is
reduced by 40 bytes.
To enable this we however need to store whether the writing-mode is
vertical or horizontal, so steal one bit from the length field for
that.

BUG=571415
Committed: https://crrev.com/f34118c23eb1eb9f76cf34bf90e2f1ad81ad2339
Cr-Commit-Position: refs/heads/master@{#368051}

[fs, 2015-12-23 16:32:03]

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

[pdr., 2016-01-04 21:54:13]

LGTM!

https://codereview.chromium.org/1548913002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/svg/SVGTextFragment.h (right):

https://codereview.chromium.org/1548913002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/svg/SVGTextFragment.h:140: // T(x,y) *
M(transform) [ * M(lengthAdjust) ] * T(-x,-y)
Supernit: The brackets around  * M(lengthAdjust) ] (here and below) were a
little confusing to me since they mix notation used in two fields. I think this
would be clearer to just leave them off:
T(x,y) * M(transform) * M(lengthAdjust) * T(-x,-y)

[fs, 2016-01-07 10:22:59]

The CQ bit was checked by fs@opera.com

[fs, 2016-01-07 10:22:59]

The patchset sent to the CQ was uploaded after l-g-t-m from pdr@chromium.org
Link to the patchset: https://codereview.chromium.org/1548913002/#ps40001
(title: "Drop [].")

[commit-bot: I haz the power, 2016-01-07 10:23:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1548913002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1548913002/40001

[fs, 2016-01-07 10:24:51]

https://codereview.chromium.org/1548913002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/core/layout/svg/SVGTextFragment.h (right):

https://codereview.chromium.org/1548913002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/core/layout/svg/SVGTextFragment.h:140: // T(x,y) *
M(transform) [ * M(lengthAdjust) ] * T(-x,-y)
On 2016/01/04 at 21:54:13, pdr wrote:
> Supernit: The brackets around  * M(lengthAdjust) ] (here and below) were a
little confusing to me since they mix notation used in two fields. I think this
would be clearer to just leave them off:
> T(x,y) * M(transform) * M(lengthAdjust) * T(-x,-y)

Removed [].

[commit-bot: I haz the power, 2016-01-07 11:17:24]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-01-07 11:18:36]

Description was changed from

==========
Store a <scale, bias> tuple for textLength scale adjustment

SVGTextFragment::lengthAdjustTransform only ever has two values that
could make it differ from the identity transform.
By storing only these two values - and as floats rather than doubles -
instead of the full AffineTransform, the size of SVGTextFragment is
reduced by 40 bytes.
To enable this we however need to store whether the writing-mode is
vertical or horizontal, so steal one bit from the length field for
that.

BUG=571415
==========

to

==========
Store a <scale, bias> tuple for textLength scale adjustment

SVGTextFragment::lengthAdjustTransform only ever has two values that
could make it differ from the identity transform.
By storing only these two values - and as floats rather than doubles -
instead of the full AffineTransform, the size of SVGTextFragment is
reduced by 40 bytes.
To enable this we however need to store whether the writing-mode is
vertical or horizontal, so steal one bit from the length field for
that.

BUG=571415

Committed: https://crrev.com/f34118c23eb1eb9f76cf34bf90e2f1ad81ad2339
Cr-Commit-Position: refs/heads/master@{#368051}
==========

[commit-bot: I haz the power, 2016-01-07 11:18:37]

Patchset 3 (id:??) landed as
https://crrev.com/f34118c23eb1eb9f76cf34bf90e2f1ad81ad2339
Cr-Commit-Position: refs/heads/master@{#368051}