Extend SVG attribute interpolation test helper to test composition modes

Extend SVG attribute interpolation test helper to test composition modes

This change adds additional parameters to assertAttributeInterpolation():
 - underlying
 - fromComposite
 - toComposite

These enable us to test composition of animations on underlying values for
SVG attribute animations.

This patch includes a failing test case as we are yet to implement SVG
attribute animation composition via Web Animations.

BUG=530436
Committed: https://crrev.com/f850b9fff8851dc876dd754f6e0d268d7d69f936
Cr-Commit-Position: refs/heads/master@{#357349}

[alancutter (OOO until 2018), 2015-10-30 10:09:03]

alancutter@chromium.org changed reviewers:
+ dstockwell@chromium.org

[alancutter (OOO until 2018), 2015-10-30 10:10:44]

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

[commit-bot: I haz the power, 2015-10-30 10:11:46]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1411043006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1411043006/1

[commit-bot: I haz the power, 2015-10-30 11:14:13]

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

[commit-bot: I haz the power, 2015-10-30 11:14:14]

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

[dstockwell, 2015-11-02 03:06:24]

lgtm

https://codereview.chromium.org/1411043006/diff/1/third_party/WebKit/LayoutTe...
File
third_party/WebKit/LayoutTests/animations/svg-attribute-composition/svg-offset-composition-expected.txt
(right):

https://codereview.chromium.org/1411043006/diff/1/third_party/WebKit/LayoutTe...
third_party/WebKit/LayoutTests/animations/svg-attribute-composition/svg-offset-composition-expected.txt:4:
PASS SMIL: Interpolate attribute <offset> add from [-0.5] add to [1] at (0) is
[0]
bit easier to parse:
<offset> from add [-0.5] to add [1] at (0) is [0]

[alancutter (OOO until 2018), 2015-11-02 03:24:44]

https://codereview.chromium.org/1411043006/diff/1/third_party/WebKit/LayoutTe...
File
third_party/WebKit/LayoutTests/animations/svg-attribute-composition/svg-offset-composition-expected.txt
(right):

https://codereview.chromium.org/1411043006/diff/1/third_party/WebKit/LayoutTe...
third_party/WebKit/LayoutTests/animations/svg-attribute-composition/svg-offset-composition-expected.txt:4:
PASS SMIL: Interpolate attribute <offset> add from [-0.5] add to [1] at (0) is
[0]
On 2015/11/02 at 03:06:24, dstockwell wrote:
> bit easier to parse:
> <offset> from add [-0.5] to add [1] at (0) is [0]

Done.

[alancutter (OOO until 2018), 2015-11-02 10:33:12]

The CQ bit was checked by alancutter@chromium.org

[alancutter (OOO until 2018), 2015-11-02 10:33:12]

The patchset sent to the CQ was uploaded after l-g-t-m from
dstockwell@chromium.org
Link to the patchset: https://codereview.chromium.org/1411043006/#ps20001
(title: "Review changes and expectations updates")

[commit-bot: I haz the power, 2015-11-02 10:33:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1411043006/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1411043006/20001

[commit-bot: I haz the power, 2015-11-02 11:23:19]

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

[commit-bot: I haz the power, 2015-11-02 11:23:19]

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

[alancutter (OOO until 2018), 2015-11-02 13:41:10]

The CQ bit was checked by alancutter@chromium.org

[alancutter (OOO until 2018), 2015-11-02 13:41:10]

The patchset sent to the CQ was uploaded after l-g-t-m from
dstockwell@chromium.org
Link to the patchset: https://codereview.chromium.org/1411043006/#ps40001
(title: "Update expectatiotnpants")

[commit-bot: I haz the power, 2015-11-02 13:41:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1411043006/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1411043006/40001

[commit-bot: I haz the power, 2015-11-02 14:37:21]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-11-02 14:38:01]

Patchset 3 (id:??) landed as
https://crrev.com/f850b9fff8851dc876dd754f6e0d268d7d69f936
Cr-Commit-Position: refs/heads/master@{#357349}