Don't walk treescopes in updateActiveStyleSheets until the resolver exists.

Don't walk treescopes in updateActiveStyleSheets until the resolver exists.

The update doesn't actually do anything until the resolver
is created, just skip the tree walk.

This also removes the special case for document from StyleSheetCollection
which didn't make any sense. It would cause us to discard the entire
resolver whenever the sheets in the document changed which is far more
work than is actually needed. We probably are missing some font invalidation
code now, but we can add that back later.

R=ojan@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/f9097c9b39eeee2eda1c1eb5832c725a6cd1e442

[esprehn, 2015-01-10 04:45:51]

https://codereview.chromium.org/836383005/diff/1/sky/engine/core/dom/StyleEng...
File sky/engine/core/dom/StyleEngine.cpp (left):

https://codereview.chromium.org/836383005/diff/1/sky/engine/core/dom/StyleEng...
sky/engine/core/dom/StyleEngine.cpp:119: clearResolver();
This didn't make sense, if we're not active then clearing the resolver doesn't
do anything.

https://codereview.chromium.org/836383005/diff/1/sky/engine/core/dom/StyleShe...
File sky/engine/core/dom/StyleSheetCollection.cpp (left):

https://codereview.chromium.org/836383005/diff/1/sky/engine/core/dom/StyleShe...
sky/engine/core/dom/StyleSheetCollection.cpp:89: engine->clearFontCache();
This is probably needed if you add/remove sheets with @font-face rules. I'll add
it back later but in a less crazy way.

[ojan, 2015-01-10 04:50:54]

lgtm

https://codereview.chromium.org/836383005/diff/1/sky/engine/core/dom/StyleShe...
File sky/engine/core/dom/StyleSheetCollection.cpp (right):

https://codereview.chromium.org/836383005/diff/1/sky/engine/core/dom/StyleShe...
sky/engine/core/dom/StyleSheetCollection.cpp:73: // TODO(esprehn): We need to
check if the resolver exists otherwise style
Fixed! Remove.

[esprehn, 2015-01-10 04:52:49]

Committed patchset #2 (id:20001) manually as
f9097c9b39eeee2eda1c1eb5832c725a6cd1e442 (presubmit successful).