Stricter treatment of SVGSVGElement::m_useCurrentView

Stricter treatment of SVGSVGElement::m_useCurrentView

m_useCurrentView being true implies that m_viewSpec is non-null. Perhaps
defensively, most code that checks it is written in a way such that it
expects that m_viewSpec can be null if m_useCurrentView is true - which
is not the case, and adds unnecessary code.
Instead change the code to adhere to the rule above, and assert that in
the various places instead.
Also add some checks of the invariant in methods that set the flag and
m_viewSpec. Refactor SVGSVGElement::setupInitialView to avoid the need
to sprinkle invariant checks "all over" it.

BUG=110195
Committed: https://crrev.com/ad443bcef2f7386e432e5c621e78640d91ef2e95
Cr-Commit-Position: refs/heads/master@{#415346}

[fs, 2016-08-30 14:24:05]

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

[commit-bot: I haz the power, 2016-08-30 14:24:29]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[fs, 2016-08-30 15:55:42]

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

[commit-bot: I haz the power, 2016-08-30 16:05:29]

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

[commit-bot: I haz the power, 2016-08-30 16:05:30]

Dry run: This issue passed the CQ dry run.

[pdr., 2016-08-30 17:50:02]

On 2016/08/30 at 15:55:42, fs wrote:
> 

LGTM

[fs, 2016-08-30 17:50:34]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2016-08-30 17:51:03]

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, 2016-08-30 17:56:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-30 17:58:28]

Description was changed from

==========
Stricter treatment of SVGSVGElement::m_useCurrentView

m_useCurrentView being true implies that m_viewSpec is non-null. Perhaps
defensively, most code that checks it is written in a way such that it
expects that m_viewSpec can be null if m_useCurrentView is true - which
is not the case, and adds unnecessary code.
Instead change the code to adhere to the rule above, and assert that in
the various places instead.
Also add some checks of the invariant in methods that set the flag and
m_viewSpec. Refactor SVGSVGElement::setupInitialView to avoid the need
to sprinkle invariant checks "all over" it.

BUG=110195
==========

to

==========
Stricter treatment of SVGSVGElement::m_useCurrentView

m_useCurrentView being true implies that m_viewSpec is non-null. Perhaps
defensively, most code that checks it is written in a way such that it
expects that m_viewSpec can be null if m_useCurrentView is true - which
is not the case, and adds unnecessary code.
Instead change the code to adhere to the rule above, and assert that in
the various places instead.
Also add some checks of the invariant in methods that set the flag and
m_viewSpec. Refactor SVGSVGElement::setupInitialView to avoid the need
to sprinkle invariant checks "all over" it.

BUG=110195

Committed: https://crrev.com/ad443bcef2f7386e432e5c621e78640d91ef2e95
Cr-Commit-Position: refs/heads/master@{#415346}
==========

[commit-bot: I haz the power, 2016-08-30 17:58:29]

Patchset 1 (id:??) landed as
https://crrev.com/ad443bcef2f7386e432e5c621e78640d91ef2e95
Cr-Commit-Position: refs/heads/master@{#415346}