Fix for printing crash when bulleted items have no bullet and we assume they do. Added assertion to help find the cause of the problem, and checks for null to prevent the crash. b=70730 r=dcone sr=waterson

layout/generic/nsBlockFrame.cpp

@@ -1223,7 +1223,7 @@ nsBlockFrame::Destroy(nsIPresContext* aPresContext)
   mAbsoluteContainer.DestroyFrames(this, aPresContext);
   // Outside bullets are not in our child-list so check for them here
   // and delete them when present.
-  if (HaveOutsideBullet()) {
+  if (mBullet) {
     mBullet->Destroy(aPresContext);
     mBullet = nsnull;
   }
@@ -2480,7 +2480,7 @@ nsBlockFrame::UpdateBulletPosition(nsBlockReflowState& aState)
   const nsStyleList* styleList;
   GetStyleData(eStyleStruct_List, (const nsStyleStruct*&) styleList);
   if (NS_STYLE_LIST_STYLE_POSITION_INSIDE == styleList->mListStylePosition) {
-    if (HaveOutsideBullet()) {
+    if (mBullet && HaveOutsideBullet()) {
       // We now have an inside bullet, but used to have an outside
       // bullet.  Adjust the frame line list
       nsLineBox* line = aState.NewLineBox(mBullet, 1, PR_FALSE);
@@ -4061,7 +4061,7 @@ nsBlockFrame::ReflowBlockFrame(nsBlockReflowState& aState,
       // rare case: an empty first line followed by a second line that
       // contains a block (example: <LI>\n<P>... ). This is where
       // the second case can happen.
-      if (HaveOutsideBullet() &&
+      if (mBullet && HaveOutsideBullet() &&
           ((aLine == mLines) ||
            ((0 == mLines->mBounds.height) && (aLine == mLines->mNext)))) {
         // Reflow the bullet
@@ -4683,7 +4683,7 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   // case is happening then the worst that will happen is that the
   // bullet frame will be reflowed twice.
   PRBool addedBullet = PR_FALSE;
-  if (HaveOutsideBullet() && (aLine == mLines) &&
+  if (mBullet && HaveOutsideBullet() && (aLine == mLines) &&
       (!aLineLayout.IsZeroHeight() || !aLine->mNext)) {
     nsHTMLReflowMetrics metrics(nsnull);
     ReflowBullet(aState, metrics);