Reviewed by Adele Peterson, Oliver Hunt, Anders Carlsson.

        Fixed <rdar://problem/5222911> Leopard9A446 : VitalSource Bookshelf 4.5: 
        Crashes when you click on sign in (stringByEvaluatingJavaScriptFromString 
        returning nil instead of "")

        I'm basically rolling out the change for <rdar://problem/4782422> because
        my testing shows that it was backwards.
        
        * html/HTMLElement.cpp:
        (dumpInnerHTML): New debug-only function to work around gdb being 
        perpetually suck-tastic.

        * page/mac/WebCoreFrameBridge.mm:
        (-[WebCoreFrameBridge stringByEvaluatingJavaScriptFromString:forceUserGesture:]):
        
        Return "", not nil. This function never used to return nil, so let's not
        start now. I've filed <rdar://problem/5283271> to cover the documentation bug,

WebKitTools:

        Reviewed by Adele Peterson, Oliver Hunt, Anders Carlsson.

        Added tests for stringByEvaluatingJavaScriptFromString.

        * DumpRenderTree/DumpRenderTree.m:
        (testStringByEvaluatingJavaScriptFromString):
        (dumpRenderTree):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@23680 268f45cc-cd09-0410-ab3c-d52691b4dbfc