[GTK] DRT fixes to pass new plugin test

bug #15457 requires a small modification in DRT in order to pass its new test. Done in attached patch.

Created an attachment (id=32112) [details]
logsrc.patch

Fix DRT.

Created an attachment (id=32113) [details]
pluginlog.patch

Small cleanup.

(From update of attachment 32112 [details])
Ok. r=me.

(From update of attachment 32113 [details])
Fine. r=me.

Created an attachment (id=32115) [details]
compilerwarning.patch

Fix compiler warnings.

(From update of attachment 32115 [details])
>      switch (variable) {
>          case NPPVpluginNameString:
> -            *((char **)value) = "WebKit Test PlugIn";
> +            *((char **)value) = (char*)"WebKit Test PlugIn";

Please change these to static_casts before commit. r=me.

(In reply to comment #6)
> (From update of attachment 32115 [details] [review])
> >      switch (variable) {
> >          case NPPVpluginNameString:
> > -            *((char **)value) = "WebKit Test PlugIn";
> > +            *((char **)value) = (char*)"WebKit Test PlugIn";
> 
> Please change these to static_casts before commit. r=me.
> 

static_cost won't work in this case. I'll use const_cast.

All patches landed as r45429, r45430 and r45431, closing.