EXT-8463 FIXED Crash in IM/chat floaters.

Reason
======

Each message in an IM/chat session has a header. The header shows an (i) button on hover and hides it when mouse leaves the header.

The button is shown by adding it as a header child and hidden by resetting the button parent.

So, if you close the IM session so that the hovered header doesn't get the MouseLeave message (e.g. by Ctrl+W),
the button gets destroyed. If you then open the IM session again and hover a message header, the destroyed button
is referenced, which leads to crash.

Fix
===

We make sure that when a hovered message header is being destroyed (by closing the IM session),
the button is detached (i.e. its parent gets reset), so that it remains usable.
I also add a couple of checks for the case when the (i) button fails to construct from XML file.

Reviewed by Mike Antipov at https://codereview.productengine.com/secondlife/r/783/

--HG--
branch : product-engine

1 files changed, 17 insertions, 1 deletions

diff --git a/indra/newview/llchathistory.cpp b/indra/newview/llchathistory.cpp
index c0fa910f86..7c33923f04 100644
--- a/indra/newview/llchathistory.cpp
+++ b/indra/newview/llchathistory.cpp
@@ -111,6 +111,12 @@ public:
 		return pInstance;
 	}
 
+	~LLChatHistoryHeader()
+	{
+		// Detach the info button so that it doesn't get destroyed (EXT-8463).
+		hideInfoCtrl();
+	}
+
 	BOOL handleMouseUp(S32 x, S32 y, MASK mask)
 	{
 		return LLPanel::handleMouseUp(x,y,mask);
@@ -382,8 +388,18 @@ protected:
 				
 		if (!sInfoCtrl)
 		{
+			// *TODO: Delete the button at exit.
 			sInfoCtrl = LLUICtrlFactory::createFromFile<LLUICtrl>("inspector_info_ctrl.xml", NULL, LLPanel::child_registry_t::instance());
-			sInfoCtrl->setCommitCallback(boost::bind(&LLChatHistoryHeader::onClickInfoCtrl, sInfoCtrl));
+			if (sInfoCtrl)
+			{
+				sInfoCtrl->setCommitCallback(boost::bind(&LLChatHistoryHeader::onClickInfoCtrl, sInfoCtrl));
+			}
+		}
+
+		if (!sInfoCtrl)
+		{
+			llassert(sInfoCtrl != NULL);
+			return;
 		}
 
 		LLTextBase* name = getChild<LLTextBase>("user_name");