[Webkit-unassigned] [Bug 112858] New: Remove upcastPointer from ActiveDOMObject constructor

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=112858

           Summary: Remove upcastPointer from ActiveDOMObject constructor
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: All
        OS/Version: All
            Status: UNCONFIRMED
          Severity: Normal
          Priority: P2
         Component: WebCore Misc.
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: russell.mcclellan at gmail.com
                CC: ap at webkit.org, sam at webkit.org, haraken at chromium.org


There's an "upcast" pointer in the ActiveDOMObject constructor.  This was introduced in the original implementation of ActiveDOMObject here (https://bugs.webkit.org/show_bug.cgi?id=21642).  There's no real documentation on what it's supposed to be used for, so I have to imagine that the idea is that it holds a pointer to the most-derived class.  I guess this was put in with the idea that it was going to be used somewhere, but for the life of me I can't see anywhere that uses it.  I've tested removing it on chromium and webkit for mac, and it seems to do fine without it (i.e. the layouttests pass).

The reason I want to remove it is I'm trying to make a whole class hierarchy (AudioNodes) into ActiveDOMObjects to solve a GC issue.  Having the extra upcast pointer argument means I'd have to thread the argument through the AudioNode constructor and the constructor of every base class derived from it, which doesn't really sound incredibly fun.

Is this actually used somewhere, and I just missed it?  This is probably the most likely scenario.  If it is not used anywhere, does this look like a safe change to you guys?

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.