Avoid exponential growth of special height reflows. (Bug 438509) r=dholbert sr=roc a=blocking1.9.1+

layout/generic/nsHTMLReflowState.cpp

@@ -405,10 +405,13 @@ nsHTMLReflowState::InitResizeFlags(nsPresContext* aPresContext)
   // If we're the descendant of a table cell that performs special height
   // reflows and we could be the child that requires them, always set
   // the vertical resize in case this is the first pass before the
-  // special height reflow.
+  // special height reflow.  However, don't do this if it actually is
+  // the special height reflow, since in that case it will already be
+  // set correctly above if we need it set.
   if (!mFlags.mVResize && mCBReflowState &&
       (IS_TABLE_CELL(mCBReflowState->frame->GetType()) || 
        mCBReflowState->mFlags.mHeightDependsOnAncestorCell) &&
+      !mCBReflowState->mFlags.mSpecialHeightReflow && 
       dependsOnCBHeight) {
     mFlags.mVResize = PR_TRUE;
     mFlags.mHeightDependsOnAncestorCell = PR_TRUE;

layout/tables/nsTableFrame.cpp

@@ -1880,7 +1880,16 @@ NS_METHOD nsTableFrame::Reflow(nsPresContext*          aPresContext,
   PRBool haveDesiredHeight = PR_FALSE;
   SetHaveReflowedColGroups(PR_FALSE);
 
-  if (aReflowState.ComputedHeight() != NS_UNCONSTRAINEDSIZE ||
+      // If we have a constrained computed height that is either
+      // different, or something inside us is different, or we're being
+      // reflowed at a different size, we could need to undo the effects
+      // of a previous special height reflow in order to distribute
+      // heights correctly again.
+  if ((aReflowState.ComputedHeight() != NS_UNCONSTRAINEDSIZE &&
+       (aReflowState.ComputedHeight() +
+          aReflowState.mComputedBorderPadding.TopBottom() != GetSize().height ||
+        NS_SUBTREE_DIRTY(this) ||
+        aReflowState.mFlags.mHResize)) ||
       // Also check mVResize, to handle the first Reflow preceding a
       // special height Reflow, when we've already had a special height
       // Reflow (where mComputedHeight would not be
@@ -1905,7 +1914,7 @@ NS_METHOD nsTableFrame::Reflow(nsPresContext*          aPresContext,
   if (NS_SUBTREE_DIRTY(this) ||
       aReflowState.ShouldReflowAllKids() ||
       IsGeometryDirty() ||
-      needToInitiateSpecialReflow) {
+      (needToInitiateSpecialReflow && aReflowState.mFlags.mVResize)) {
     // see if an extra reflow will be necessary in pagination mode when there is a specified table height 
     if (isPaginated && !GetPrevInFlow() && (NS_UNCONSTRAINEDSIZE != aReflowState.availableHeight)) {
       nscoord tableSpecifiedHeight = CalcBorderBoxHeight(aReflowState);