Begin stubbing out a new KeyedEncoder class
https://bugs.webkit.org/show_bug.cgi?id=116456

Reviewed by Sam Weinig.

This class (and it's coming counterpart, KeyedDecoder) will be used for serializing
object graphs to a tree-like structure of dictionaries. It is up to individual ports to
serialize them further (for example, on Mac they could be serialized to CFPropertyList objects).

This will be used for serializing session storage state but I hope that it can be used for serializing
back forward state in the future as our current implementation of back forward state serialization
is fragile and depends on our IPC layer's binary encoding(!).

* Shared/KeyedCodingValue.h: Added.
* Shared/KeyedEncoder.cpp: Added.
* Shared/KeyedEncoder.h: Added.

* WebKit2.xcodeproj/project.pbxproj:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150377 268f45cc-cd09-0410-ab3c-d52691b4dbfc
[Qt] REGRESSION(r149457): some fast/exclusions tests are failing
https://bugs.webkit.org/show_bug.cgi?id=115511

Reviewed by Andreas Kling.

Unskipping the exclusions tests on Qt. They were fixed by https://bugs.webkit.org/show_bug.cgi?id=116115.

* platform/qt/TestExpectations:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150378 268f45cc-cd09-0410-ab3c-d52691b4dbfc