Use an AutoRestore to restore mY in nsBlockReflowState::FlowAndPlaceFloat. (Bug 563584, patch 7) r=roc

layout/generic/nsBlockReflowState.cpp

@@ -50,6 +50,7 @@
 #include "nsGkAtoms.h"
 #include "nsIFrame.h"
 #include "nsFrameManager.h"
+#include "mozilla/AutoRestore.h"
 
 #include "nsINameSpaceManager.h"
 
@@ -58,6 +59,8 @@
 #include "nsBlockDebugFlags.h"
 #endif
 
+using namespace mozilla;
+
 nsBlockReflowState::nsBlockReflowState(const nsHTMLReflowState& aReflowState,
                                        nsPresContext* aPresContext,
                                        nsBlockFrame* aFrame,
@@ -670,7 +673,9 @@ nsBlockReflowState::FlowAndPlaceFloat(nsIFrame*       aFloat,
   // necessary because any adjustments to mY during the float
   // placement are for the float only, not for any non-floating
   // content.
-  nscoord saveY = mY;
+  AutoRestore<nscoord> restoreY(mY);
+  // FIXME: Should give AutoRestore a getter for the value to avoid this.
+  const nscoord saveY = mY;
 
   // Grab the float's display information
   const nsStyleDisplay* floatDisplay = aFloat->GetStyleDisplay();
@@ -717,7 +722,6 @@ nsBlockReflowState::FlowAndPlaceFloat(nsIFrame*       aFloat,
   for (;;) {
     if (floatAvailableSpace.mRect.height <= 0) {
       // No space, nowhere to put anything.
-      mY = saveY;
       return PR_FALSE;
     }
 
@@ -839,7 +843,6 @@ nsBlockReflowState::FlowAndPlaceFloat(nsIFrame*       aFloat,
        pushedDown) &&
       aFloat->GetSize().height + floatMargin.TopBottom() >
         mContentArea.height - floatY) {
-    mY = saveY;
     return PR_FALSE;
   }
 
@@ -904,9 +907,6 @@ nsBlockReflowState::FlowAndPlaceFloat(nsIFrame*       aFloat,
          region.x, region.y, region.width, region.height);
 #endif
 
-  // Now restore mY
-  mY = saveY;
-
 #ifdef DEBUG
   if (nsBlockFrame::gNoisyReflow) {
     nsRect r = aFloat->GetRect();