Overhaul WebKit2 preferences code

Reviewed by Anders Carlsson.

- Reduces the number of places you have to touch to add a new preference
  (From 9 down to 4, but with a bit of elbow grease, we should get that
   down to 2 or 3).
- Add hooks so that platforms can initialize the preferences based on an
  identifier. This is currently only used on the Mac to initialize a
  preference store from NSUserDefaults and autosave the changes to disk.
  It is not yet enabled due to no way to set the identifier from client
  code.

* Shared/WebPageCreationParameters.cpp:
Add necessary #include of WebCoreArgumentCoders.h which is now needed
due to cleanup in WebPreferencesStore.h.

* Shared/WebPreferencesStore.cpp:
(WebKit::WebPreferencesStore::WebPreferencesStore):
(WebKit::WebPreferencesStore::encode):
(WebKit::WebPreferencesStore::decode):
(WebKit::defaultValueForKey):
(WebKit::setValueForKey):
(WebKit::valueForKey):
(WebKit::WebPreferencesStore::setStringValueForKey):
(WebKit::WebPreferencesStore::getStringValueForKey):
(WebKit::WebPreferencesStore::setBoolValueForKey):
(WebKit::WebPreferencesStore::getBoolValueForKey):
(WebKit::WebPreferencesStore::setUInt32ValueForKey):
(WebKit::WebPreferencesStore::getUInt32ValueForKey):
* Shared/WebPreferencesStore.h:
Complete overhaul of this class to store the preferences as
a set of HashMaps and use macros to define the keys and default
values.

* UIProcess/API/C/WKPreferences.cpp:
(WKPreferencesGetFontSmoothingLevel):
Add cast to keep conversion function working.

* UIProcess/WebPreferences.cpp:
(WebKit::WebPreferences::WebPreferences): Add identifier constructor.
(WebKit::WebPreferences::updateStringValueForKey):
(WebKit::WebPreferences::updateBoolValueForKey):
(WebKit::WebPreferences::updateUInt32ValueForKey):
Add type based updaters. These currently give hooks to the platform and
call the generic update, but in the future, we can use this to optimize
updating preferences to not send the entire store for each change.

* UIProcess/WebPreferences.h:
Generate the getters and setters via macro instantiation.

* UIProcess/cf/WebPreferencesCF.cpp: Added.
(WebKit::WebPreferences::platformInitializeStore):
(WebKit::WebPreferences::platformUpdateStringValueForKey):
(WebKit::WebPreferences::platformUpdateBoolValueForKey):
(WebKit::WebPreferences::platformUpdateUInt32ValueForKey):
Stubbed out.

* UIProcess/mac/WebPreferencesMac.mm: Added.
(WebKit::makeKey):
(WebKit::setStringValueIfInUserDefaults):
(WebKit::setBoolValueIfInUserDefaults):
(WebKit::setUInt32ValueIfInUserDefaults):
(WebKit::WebPreferences::platformInitializeStore):
(WebKit::WebPreferences::platformUpdateStringValueForKey):
(WebKit::WebPreferences::platformUpdateBoolValueForKey):
(WebKit::WebPreferences::platformUpdateUInt32ValueForKey):
Use the platform hooks to initialize and update the store from
NSUserDefaults.
        
* UIProcess/qt/WebPreferencesQt.cpp: Added.
(WebKit::WebPreferences::platformInitializeStore):
(WebKit::WebPreferences::platformUpdateStringValueForKey):
(WebKit::WebPreferences::platformUpdateBoolValueForKey):
(WebKit::WebPreferences::platformUpdateUInt32ValueForKey):
Stubbed out.

* WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::updatePreferences):
* WebProcess/WebPage/win/WebPageWin.cpp:
(WebKit::WebPage::platformPreferencesDidChange):
Update to pull the value using the new type based getters.

* WebKit2.pro:
* WebKit2.xcodeproj/project.pbxproj:
* win/WebKit2.vcproj:
Add new files.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@73154 268f45cc-cd09-0410-ab3c-d52691b4dbfc