Resolves: fdo#53460 crashes after casting SwTxtFrm to unrelated SwLayoutFrm

We still can't use ctrl+up to shrink the height of a row that has a table in
it, but it doesn't crash anymore.

This code presumably isn't truly table-in-table aware and should somehow step
"over" the embedded table and not "into" it, which is what I guess it is doing
here.

(cherry picked from commit 5141f2e0d89a8a10f0009bea40cc5cd15bf4fcc8)

Conflicts:
	sw/source/core/layout/frmtool.cxx

Change-Id: I0e4c757c75438a89eb7721de32990f2f21c1ad8b

1 files changed, 8 insertions, 9 deletions

diff --git a/sw/source/core/layout/frmtool.cxx b/sw/source/core/layout/frmtool.cxx
index a4a0c7946e61..5ea9e503784f 100644
--- a/sw/source/core/layout/frmtool.cxx
+++ b/sw/source/core/layout/frmtool.cxx
@@ -3190,12 +3190,11 @@ static SwTwips lcl_CalcCellRstHeight( SwLayoutFrm *pCell )
     {
         long nRstHeight = 0;
         SwFrm *pLow = pCell->Lower();
-        do
-        {   nRstHeight += ::CalcRowRstHeight( (SwLayoutFrm*)pLow );
+        while (pLow && pLow->IsLayoutFrm())
+        {
+            nRstHeight += ::CalcRowRstHeight(static_cast<SwLayoutFrm*>(pLow));
             pLow = pLow->GetNext();
-
-        } while ( pLow );
-
+        }
         return nRstHeight;
     }
 }
@@ -3203,11 +3202,11 @@ static SwTwips lcl_CalcCellRstHeight( SwLayoutFrm *pCell )
 SwTwips CalcRowRstHeight( SwLayoutFrm *pRow )
 {
     SwTwips nRstHeight = LONG_MAX;
-    SwLayoutFrm *pLow = (SwLayoutFrm*)pRow->Lower();
-    while ( pLow )
+    SwFrm *pLow = pRow->Lower();
+    while (pLow && pLow->IsLayoutFrm())
     {
-        nRstHeight = std::min( nRstHeight, ::lcl_CalcCellRstHeight( pLow ) );
-        pLow = (SwLayoutFrm*)pLow->GetNext();
+        nRstHeight = std::min(nRstHeight, ::lcl_CalcCellRstHeight(static_cast<SwLayoutFrm*>(pLow)));
+        pLow = pLow->GetNext();
     }
     return nRstHeight;
 }