Bug 738192 follow-up. Re-enable layout/reftests/svg/dynamic-text-04.svg after fixing MarkDirtyBitsOnDescendants. r=me.

layout/reftests/svg/reftest.list

@@ -98,7 +98,7 @@ fuzzy-if(/^Windows\x20NT\x206\.1/.test(http.oscpu),1,2) == clipPath-and-shape-re
 == dynamic-text-01.svg dynamic-text-01-ref.svg
 == dynamic-text-02.svg dynamic-text-02-ref.svg
 == dynamic-text-03.svg dynamic-text-03-ref.svg
-#random-if(/^Windows\x20NT\x205\.1/.test(http.oscpu)) == dynamic-text-04.svg dynamic-text-04-ref.svg # bug 421587 for WinXP
+random-if(/^Windows\x20NT\x205\.1/.test(http.oscpu)) == dynamic-text-04.svg dynamic-text-04-ref.svg # bug 421587 for WinXP
 == dynamic-text-05.svg pass.svg
 == dynamic-text-06.svg pass.svg
 == dynamic-text-07.svg dynamic-text-07-ref.svg

layout/svg/base/src/nsSVGTextFrame.cpp

@@ -278,15 +278,17 @@ nsSVGTextFrame::GetCanvasTM()
 static void
 MarkDirtyBitsOnDescendants(nsIFrame *aFrame)
 {
-  if (aFrame->GetStateBits() & (NS_FRAME_IS_DIRTY | NS_FRAME_FIRST_REFLOW)) {
+  // Do not skip marking of aFrame or any of its descendants if they have
-    // Nothing to do if we're already dirty, or if the outer-<svg>
+  // the NS_FRAME_IS_DIRTY set, because some of their descendants may not
-    // hasn't yet had its initial reflow.
+  // have it set, and we need all descendants to be dirty.
+  if (aFrame->GetStateBits() & (NS_FRAME_FIRST_REFLOW)) {
+    // Nothing to do if our outer-<svg> hasn't yet had its initial reflow.
     return;
   }
   nsIFrame* kid = aFrame->GetFirstPrincipalChild();
   while (kid) {
     nsISVGChildFrame* svgkid = do_QueryFrame(kid);
-    if (svgkid && !(kid->GetStateBits() & NS_FRAME_IS_DIRTY)) {
+    if (svgkid) {
       MarkDirtyBitsOnDescendants(kid);
       kid->AddStateBits(NS_FRAME_IS_DIRTY);
     }