Reviewed by John Sullivan.

    Reviewed by John Sullivan.

        Move the developer extras preference to WebPreferences.

        * WebView/WebPreferenceKeysPrivate.h: Add WebKitDeveloperExtrasEnabledPreferenceKey
        * WebView/WebPreferences.m:
        (+[WebPreferences initialize]): Initialize WebKitDeveloperExtrasEnabledPreferenceKey to NO.
        (-[WebPreferences developerExtrasEnabled]): Check DisableWebKitDeveloperExtras, WebKitDeveloperExtras
          and IncludeDebugMenu in addition to WebKitDeveloperExtrasEnabledPreferenceKey.
        (-[WebPreferences setDeveloperExtrasEnabled:]): Set WebKitDeveloperExtrasEnabledPreferenceKey.
        * WebView/WebPreferencesPrivate.h: Add developerExtrasEnabled and setDeveloperExtrasEnabled:.
        * WebView/WebView.mm:
        (+[WebView _developerExtrasEnabled]): Removed.
        (-[WebView _preferencesChangedNotification:]): Check the WebPreferences object for developerExtrasEnabled.
        * WebView/WebViewPrivate.h: Removed _developerExtrasEnabled.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@27332 268f45cc-cd09-0410-ab3c-d52691b4dbfc