Back out 307158 to fix 310736. GetActualScrollbarSizes is not meaningful on a frame in the middle of reflow.

layout/generic/nsBlockFrame.cpp

@@ -75,7 +75,6 @@
 #include "nsLayoutErrors.h"
 #include "nsAutoPtr.h"
 #include "nsIServiceManager.h"
-#include "nsIScrollableFrame.h"
 #ifdef ACCESSIBILITY
 #include "nsIAccessibilityService.h"
 #endif
@@ -611,23 +610,13 @@ CalculateContainingBlockSizeForAbsolutes(const nsHTMLReflowState& aReflowState,
       // heck did it end up wrapping this block frame?
       NS_ASSERTION(aLastRS->frame->GetStyleDisplay()->IsBlockLevel(),
                    "Wrapping frame should be block-level");
-      // Scrollbars need to be specifically excluded, if present, because they are outside the
-      // padding-edge. We need better APIs for getting the various boxes from a frame.
-      nsIScrollableFrame* scrollFrame;
-      CallQueryInterface(aLastRS->frame, &scrollFrame);
-      nsMargin scrollbars(0,0,0,0);
-      if (scrollFrame) {
-        scrollbars = scrollFrame->GetActualScrollbarSizes();
-      }
       // We found a reflow state for the outermost wrapping frame, so use
       // its computed metrics if available
       if (aLastRS->mComputedWidth != NS_UNCONSTRAINEDSIZE) {
-        cbSize.width = PR_MAX(0,
-          aLastRS->mComputedWidth + aLastRS->mComputedPadding.LeftRight() - scrollbars.LeftRight());
+        cbSize.width = aLastRS->mComputedWidth + aLastRS->mComputedPadding.LeftRight();
       }
       if (aLastRS->mComputedHeight != NS_UNCONSTRAINEDSIZE) {
-        cbSize.height = PR_MAX(0,
-          aLastRS->mComputedHeight + aLastRS->mComputedPadding.TopBottom() - scrollbars.TopBottom());
+        cbSize.height = aLastRS->mComputedHeight + aLastRS->mComputedPadding.TopBottom();
       }
     }
   }