Use double precision in SVGLengthContext::convertValueToUserUnits

Use double precision in SVGLengthContext::convertValueToUserUnits

This method does a bunch of <float> * <double> operations, which tickles
UBSANs float-overflow warning when the result is stored back into the
float (single precision) local variable.
We clamp the result to a narrow enough range already at the end (and
hence won't see any effects of the overflow, at least assuming IEEE754),
but might as well use a double precision local variable, since that
actually seems to save a few instructions while also avoiding the
overflowing conversion.

BUG=675140
Committed: https://crrev.com/44dabf826136f0ddfab6f908036b68c7dce9a616
Cr-Commit-Position: refs/heads/master@{#440056}

[fs, 2016-12-20 12:44:16]

The CQ bit was checked by fs@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2016-12-20 12:44:29]

Dry run: 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, 2016-12-20 15:58:03]

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

[commit-bot: I haz the power, 2016-12-20 15:58:04]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[fs, 2016-12-20 17:01:38]

The CQ bit was checked by fs@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2016-12-20 17:02:32]

Dry run: 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, 2016-12-20 18:33:08]

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

[commit-bot: I haz the power, 2016-12-20 18:33:10]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[fs, 2016-12-20 18:48:22]

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

[pdr., 2016-12-20 23:55:36]

On 2016/12/20 at 18:48:22, fs wrote:
> 

LGTM

[fs, 2016-12-21 08:44:33]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2016-12-21 08:44:49]

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, 2016-12-21 08:49:41]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1482309873135450,
"parent_rev": "c69e469c80e49ce1af14db8eccb81ec1fcae761e", "commit_rev":
"accc951a263f39a9eecf39aee67aaa9e0fa07aef"}

[commit-bot: I haz the power, 2016-12-21 08:50:07]

Description was changed from

==========
Use double precision in SVGLengthContext::convertValueToUserUnits

This method does a bunch of <float> * <double> operations, which tickles
UBSANs float-overflow warning when the result is stored back into the
float (single precision) local variable.
We clamp the result to a narrow enough range already at the end (and
hence won't see any effects of the overflow, at least assuming IEEE754),
but might as well use a double precision local variable, since that
actually seems to save a few instructions while also avoiding the
overflowing conversion.

BUG=675140
==========

to

==========
Use double precision in SVGLengthContext::convertValueToUserUnits

This method does a bunch of <float> * <double> operations, which tickles
UBSANs float-overflow warning when the result is stored back into the
float (single precision) local variable.
We clamp the result to a narrow enough range already at the end (and
hence won't see any effects of the overflow, at least assuming IEEE754),
but might as well use a double precision local variable, since that
actually seems to save a few instructions while also avoiding the
overflowing conversion.

BUG=675140

Review-Url: https://codereview.chromium.org/2591663003
==========

[commit-bot: I haz the power, 2016-12-21 08:50:08]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-12-21 08:53:00]

Description was changed from

==========
Use double precision in SVGLengthContext::convertValueToUserUnits

This method does a bunch of <float> * <double> operations, which tickles
UBSANs float-overflow warning when the result is stored back into the
float (single precision) local variable.
We clamp the result to a narrow enough range already at the end (and
hence won't see any effects of the overflow, at least assuming IEEE754),
but might as well use a double precision local variable, since that
actually seems to save a few instructions while also avoiding the
overflowing conversion.

BUG=675140

Review-Url: https://codereview.chromium.org/2591663003
==========

to

==========
Use double precision in SVGLengthContext::convertValueToUserUnits

This method does a bunch of <float> * <double> operations, which tickles
UBSANs float-overflow warning when the result is stored back into the
float (single precision) local variable.
We clamp the result to a narrow enough range already at the end (and
hence won't see any effects of the overflow, at least assuming IEEE754),
but might as well use a double precision local variable, since that
actually seems to save a few instructions while also avoiding the
overflowing conversion.

BUG=675140

Committed: https://crrev.com/44dabf826136f0ddfab6f908036b68c7dce9a616
Cr-Commit-Position: refs/heads/master@{#440056}
==========

[commit-bot: I haz the power, 2016-12-21 08:53:01]

Patchset 2 (id:??) landed as
https://crrev.com/44dabf826136f0ddfab6f908036b68c7dce9a616
Cr-Commit-Position: refs/heads/master@{#440056}