Redundant String ref/deref calls in V8 bindings

[Jens Alfke]

There are unnecessary extra ref/derefs of WebCore::StringImps in the V8/WebCore bindings. This happens because the trivial inline function 'toString' defined in V8Binding.h, which is supposed to be a no-op, actually isn't:

    inline String toString(const String& string)
    {
        return string;
    }

GCC generates both a String constructor and destructor call as a result of inlining this, which each 
generate code. This can be fixed by changing the result type to "const String&", after which the 
function truly is a no-op. 

This simple change shaves 97kbytes off of a release Mac build of Chromium, and will have some benefit in performance (though I haven't benchmarked it.)

[Jens Alfke]

Previously reported against Chromium as http://code.google.com/p/chromium/issues/detail?id=25252

[Jens Alfke]

Created attachment 41511 [details]
patch 1

[Eric Seidel (no email)]

Comment on attachment 41511 [details]
patch 1

Needs a ChangeLog.  Otherwise this looks fine.  I trust you can add one when you commit.  :)  If you're not a committer, please post a new patch w/ ChangeLog.

[Jens Alfke]

Patch was landed yesterday as http://trac.webkit.org/changeset/49890