No need to re-parse empty set of injected stylesheets.

No need to re-parse empty set of injected stylesheets.

setCompatibilityMode invalidates the injected stylesheet cache which means
styleResolverChanged() and an updating of the active stylesheets list. The
reason is that the injected stylesheets need to be re-parsed with the
correct strict/quirks mode. If the list of injected stylesheets is empty,
there are no stylesheets to reparse, so avoid styleResolverChanged().

This might not mean much in practice, depending on where the compat mode
may change, but the styleResolverChanged was noise while trying to analyze
the bug in question.

BUG=393480
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181125

[rune, 2014-08-19 09:39:13]

PTAL

[esprehn, 2014-08-19 11:30:59]

https://codereview.chromium.org/468903002/diff/1/Source/core/dom/StyleEngine.cpp
File Source/core/dom/StyleEngine.cpp (right):

https://codereview.chromium.org/468903002/diff/1/Source/core/dom/StyleEngine....
Source/core/dom/StyleEngine.cpp:236: if (!m_injectedAuthorStyleSheets.isEmpty())
Is this correct? If the cache is empty why don't we need to recompute it and set
the dirty bit in there?

[rune, 2014-08-19 13:31:16]

https://codereview.chromium.org/468903002/diff/1/Source/core/dom/StyleEngine.cpp
File Source/core/dom/StyleEngine.cpp (right):

https://codereview.chromium.org/468903002/diff/1/Source/core/dom/StyleEngine....
Source/core/dom/StyleEngine.cpp:236: if (!m_injectedAuthorStyleSheets.isEmpty())
On 2014/08/19 11:30:59, esprehn wrote:
> Is this correct? If the cache is empty why don't we need to recompute it and
set
> the dirty bit in there?

The cache is the set of injected stylesheet which apply to the url of the
document for this style engine. That cache needs to be updated when the list of
injected stylesheets change since there might be stylesheets in the cache which
are removed from the global list, or newly added injected stylesheets which may
match the url of this document.

For a compat mode change, however, the list of injected stylesheets doesn't
change, so the list of matching stylesheets (the cache) should not change, but
their contents need to be reparsed. If the cache is empty, there are no
stylesheets to reparse.

A question is if injected stylesheets really should or need follow the
compatMode of the document into which they are inserted.

[rune, 2014-08-29 09:02:22]

ping

[esprehn, 2014-08-29 20:09:55]

lgtm

[rune, 2014-08-29 21:23:47]

The CQ bit was checked by rune@opera.com

[commit-bot: I haz the power, 2014-08-30 00:44:11]

Committed patchset #1 (id:1) as 181125