Crash on any help access when building 3.4.0 without qt web kit under VS2012, x64

Re: Visual Studio 2012, x64 build of Qt Creator 3.4.0 (otherwise I would just use a prepackaged binary). Possible bug in help plugin source, helpplugin.cpp

My current task requires me to build without the qt web kit. Therefore line 385 of helpplugin.cpp assures that a default contstructed factory that does nothing will be used... that results in a crash on line 390 when the functor of a NULL pointer is used.

I.E.
Line 385 constructs a default factory object. (That's what QHash::value() does when something isn't in the map) Therefore when testing on 386, the if(!factory) test fails and a TextBrowserHelpViewer() factory is never assigned to the factory function pointer. Furthermore, the QTC_ASSERT macro fails to capture the error as well since the map instanced a valid ViewerFactory base instance that does nothing.

Suggest using safer if(!factory && factories.contains(QLatin1String("qtwebkit")) instead of if(!factory) on line 384. It makes no sense to attempt to ask for a factory object from something that may not be in the hash map by instancing a generic one.