Avoid endless loop deleting CFGAS_GEFont.

It's a ref-counted class, so if we're in the destructor, the ref
count has hit zero. We can't make a new ref pointer to itself here,
as it will re-invoke the destructor when it goes out of scope. This
should have been an obvious anti-pattern in hindsight.

The object in question can't be in the m_pFontManager, since the font
manager retains a reference, and we wouldn't get to this destructor
while that is present. So the cleanup isn't required.

Fixing this revealed a free-delete mismatch in cxfa_textlayout.cpp.
I also converted to use unique_ptrs in a few places near this issue.

Fixing this revealed a UAF in CFGAS_GEFont, memcpy'ing a RetainPtr
is not a good idea as it doesn't bump the ref count.

Also protect and friend the CFGAS_GEFont destructor, to make sure
random deletes don't happen.

Also kill off a const cast, and remove unnecessary conversion to
retain_ptr when we already have one.

TEST=look for absence of -11 in XFA corpus test logs, bots not
     currently noticing the segv.  Argh.

Review-Url: https://codereview.chromium.org/2631703003

1 files changed, 1 insertions, 0 deletions

diff --git a/core/fxcrt/cfx_retain_ptr.h b/core/fxcrt/cfx_retain_ptr.h
index f70faf1464..62b26942ba 100644
--- a/core/fxcrt/cfx_retain_ptr.h
+++ b/core/fxcrt/cfx_retain_ptr.h
@@ -83,6 +83,7 @@ class CFX_Retainable {
 
   void Retain() { ++m_nRefCount; }
   void Release() {
+    ASSERT(m_nRefCount > 0);
     if (--m_nRefCount == 0)
       delete this;
   }