[webkit-dev] inconsistent refptr count between Frame and Document

[Luke Kenneth Casson Leighton]

https://bugs.webkit.org/show_bug.cgi?id=20935

i've identified a number of areas where people are writing "FIXMEs"
and "TODOs" that are related to refcount inconsistency between Frame
and Document.  the key to the issue is, i believe, that it is
necessary to increase the refcount on all member objects which are
contained within an object.

in Document's case, that's m_frame, m_styleSheets and many other objects.

failure to observe the practice of increasing the parent's refcount
when a member object is referred to results in issues such as #20403,
at the very least.

it _may_ be that, due to the possibility of Document* being destroyed
_outside_ of the control of objects that have refs to it
(Document::detach()) - that this is the _only_ circumstance where this
is a problem - i damn well hope so because the design decisions that
need to be taken to solve this right across the board are pretty damn
tough ones.

it _may_ be that the problem is isolated to Document and the
interaction between Document and Frame.

i've outlined enough, here, and in the above bug-report, for other
people to be able to investigate this issue more thoroughly.  if
anyone has any questions, or requires clarification, please do contact
me (direct by email).

l.