Reviewed by Adam Barth.

        https://bugs.webkit.org/show_bug.cgi?id=27494

        Fixes an issue that can cause a crash or unexpected behavior when calling
        WebCore::ScriptSourceCode::source on a cached script.

        * GNUmakefile.am:
        * WebCore.gypi:
        * WebCore.pro:
        * WebCore.vcproj/WebCore.vcproj:
        * WebCore.xcodeproj/project.pbxproj:
        * bindings/js/CachedScriptSourceProvider.h: Modified to inherit from
        WebCore::ScriptSourceCode.
        (WebCore::CachedScriptSourceProvider::source):
        (WebCore::CachedScriptSourceProvider::CachedScriptSourceProvider):
        * bindings/js/ScriptSourceCode.h:
        (WebCore::ScriptSourceCode::ScriptSourceCode): Separated out source provider and
        rewrote to use WebCore::ScriptSourceProvider.
        (WebCore::ScriptSourceCode::source):
        * bindings/js/ScriptSourceProvider.h: Added.
        (WebCore::ScriptSourceProvider::ScriptSourceProvider):
        (WebCore::ScriptSourceProvider::~ScriptSourceProvider):
        * bindings/js/StringSourceProvider.h: Modified to inherit from
        WebCore::ScriptSourceCode.
        (WebCore::StringSourceProvider::StringSourceProvider):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@46216 268f45cc-cd09-0410-ab3c-d52691b4dbfc