Bug 1172239. Make vertically-resizing scrollframes reflow their percent-height descendants if necessary, and remove nsChangeHint_NeedDirtyReflow for height changes. r=bz

--HG--
extra : commitid : Hbu6gzLSBUp
extra : rebase_source : 4d0b03a0ff2e53ea262ef6c17630b450b535dc3c

layout/generic/nsGfxScrollFrame.cpp

@@ -505,6 +505,9 @@ nsHTMLScrollFrame::ReflowScrolledFrame(ScrollReflowState* aState,
   kidReflowState.SetComputedBSize(computedBSize);
   kidReflowState.ComputedMinBSize() = computedMinBSize;
   kidReflowState.ComputedMaxBSize() = computedMaxBSize;
+  if (aState->mReflowState.IsBResize()) {
+    kidReflowState.SetBResize(true);
+  }
 
   // Temporarily set mHasHorizontalScrollbar/mHasVerticalScrollbar to
   // reflect our assumptions while we reflow the child.

layout/style/nsStyleStruct.cpp

@@ -1604,7 +1604,7 @@ nsChangeHint nsStylePosition::CalcDifference(const nsStylePosition& aOther) cons
     // clear ancestor intrinsics!
     return NS_CombineHint(hint, nsChangeHint_NeedReflow |
         nsChangeHint_ClearAncestorIntrinsics |
-        nsChangeHint_ClearDescendantIntrinsics | nsChangeHint_NeedDirtyReflow |
+        nsChangeHint_ClearDescendantIntrinsics |
         nsChangeHint_ReflowChangesSizeOrPosition);
   }