C++ DO_GLOBAL_REFLOW_COUNT函數代碼示例

NS_IMETHODIMP 
nsLegendFrame::Reflow(nsPresContext*          aPresContext,
                     nsHTMLReflowMetrics&     aDesiredSize,
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsLegendFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  if (mState & NS_FRAME_FIRST_REFLOW) {
    nsFormControlFrame::RegUnRegAccessKey(static_cast<nsIFrame*>(this), PR_TRUE);
  }
  return nsBlockFrame::Reflow(aPresContext, aDesiredSize, aReflowState, aStatus);
}

NS_METHOD
nsImageControlFrame::Reflow(nsPresContext*         aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsImageControlFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  if (!GetPrevInFlow() && (mState & NS_FRAME_FIRST_REFLOW)) {
    nsFormControlFrame::RegUnRegAccessKey(this, PR_TRUE);
  }
  return nsImageControlFrameSuper::Reflow(aPresContext, aDesiredSize, aReflowState, aStatus);
}

NS_IMETHODIMP
nsRootBoxFrame::Reflow(nsPresContext*           aPresContext,
                       nsHTMLReflowMetrics&     aDesiredSize,
                       const nsHTMLReflowState& aReflowState,
                       nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsRootBoxFrame");

#ifdef DEBUG_REFLOW
  gReflows++;
  printf("----Reflow %d----\n", gReflows);
#endif
  return nsBoxFrame::Reflow(aPresContext, aDesiredSize, aReflowState, aStatus);
}

nsresult
nsPlaceholderFrame::Reflow(nsPresContext*           aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
#ifdef DEBUG
  // We should be getting reflowed before our out-of-flow.
  // If this is our first reflow, and our out-of-flow has already received its
  // first reflow (before us), complain.
  // XXXdholbert This "look for a previous continuation or IB-split sibling"
  // code could use nsLayoutUtils::GetPrevContinuationOrIBSplitSibling(), if
  // we ever add a function like that. (We currently have a "Next" version.)
  if ((GetStateBits() & NS_FRAME_FIRST_REFLOW) &&
      !(mOutOfFlowFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {

    // Unfortunately, this can currently happen when the placeholder is in a
    // later continuation or later IB-split sibling than its out-of-flow (as
    // is the case in some of our existing unit tests). So for now, in that
    // case, we'll warn instead of asserting.
    bool isInContinuationOrIBSplit = false;
    nsIFrame* ancestor = this;
    while ((ancestor = ancestor->GetParent())) {
      if (ancestor->GetPrevContinuation() ||
          ancestor->Properties().Get(IBSplitPrevSibling())) {
        isInContinuationOrIBSplit = true;
        break;
      }
    }

    if (isInContinuationOrIBSplit) {
      NS_WARNING("Out-of-flow frame got reflowed before its placeholder");
    } else {
      NS_ERROR("Out-of-flow frame got reflowed before its placeholder");
    }
  }
#endif

  DO_GLOBAL_REFLOW_COUNT("nsPlaceholderFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  aDesiredSize.Width() = 0;
  aDesiredSize.Height() = 0;

  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return NS_OK;
}

nsresult
nsLeafFrame::Reflow(nsPresContext* aPresContext,
                    nsHTMLReflowMetrics& aMetrics,
                    const nsHTMLReflowState& aReflowState,
                    nsReflowStatus& aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsLeafFrame");
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                 ("enter nsLeafFrame::Reflow: aMaxSize=%d,%d",
                  aReflowState.AvailableWidth(), aReflowState.AvailableHeight()));

  NS_PRECONDITION(mState & NS_FRAME_IN_REFLOW, "frame is not in reflow");

  DoReflow(aPresContext, aMetrics, aReflowState, aStatus);

  FinishAndStoreOverflow(&aMetrics);
  return NS_OK;
}

void
nsTableColFrame::Reflow(nsPresContext*          aPresContext,
                                  nsHTMLReflowMetrics&     aDesiredSize,
                                  const nsHTMLReflowState& aReflowState,
                                  nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsTableColFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  aDesiredSize.ClearSize();
  const nsStyleVisibility* colVis = StyleVisibility();
  bool collapseCol = (NS_STYLE_VISIBILITY_COLLAPSE == colVis->mVisible);
  if (collapseCol) {
    nsTableFrame* tableFrame = nsTableFrame::GetTableFrame(this);
    tableFrame->SetNeedToCollapse(true);
  }
  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
}

NS_IMETHODIMP
nsPlaceholderFrame::Reflow(nsPresContext*          aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsPlaceholderFrame", aReflowState.reason);
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  aDesiredSize.width = 0;
  aDesiredSize.height = 0;
  aDesiredSize.ascent = 0;
  aDesiredSize.descent = 0;
  if (aDesiredSize.mComputeMEW) {
    aDesiredSize.mMaxElementWidth = 0;
  }

  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return NS_OK;
}

NS_IMETHODIMP nsProgressFrame::Reflow(nsPresContext*           aPresContext,
                                      nsHTMLReflowMetrics&     aDesiredSize,
                                      const nsHTMLReflowState& aReflowState,
                                      nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsProgressFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);

  NS_ASSERTION(mBarDiv, "Progress bar div must exist!");
  NS_ASSERTION(!GetPrevContinuation(),
               "nsProgressFrame should not have continuations; if it does we "
               "need to call RegUnregAccessKey only for the first.");

  if (mState & NS_FRAME_FIRST_REFLOW) {
    nsFormControlFrame::RegUnRegAccessKey(this, true);
  }

  nsIFrame* barFrame = mBarDiv->GetPrimaryFrame();
  NS_ASSERTION(barFrame, "The progress frame should have a child with a frame!");

  ReflowBarFrame(barFrame, aPresContext, aReflowState, aStatus);

  aDesiredSize.width = aReflowState.ComputedWidth() +
                       aReflowState.mComputedBorderPadding.LeftRight();
  aDesiredSize.height = aReflowState.ComputedHeight() +
                        aReflowState.mComputedBorderPadding.TopBottom();
  aDesiredSize.height = NS_CSS_MINMAX(aDesiredSize.height,
                                      aReflowState.mComputedMinHeight,
                                      aReflowState.mComputedMaxHeight);

  aDesiredSize.SetOverflowAreasToDesiredBounds();
  ConsiderChildOverflow(aDesiredSize.mOverflowAreas, barFrame);
  FinishAndStoreOverflow(&aDesiredSize);

  aStatus = NS_FRAME_COMPLETE;

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);

  return NS_OK;
}

NS_METHOD nsTableColGroupFrame::Reflow(nsPresContext*          aPresContext,
                                       nsHTMLReflowMetrics&     aDesiredSize,
                                       const nsHTMLReflowState& aReflowState,
                                       nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsTableColGroupFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  NS_ASSERTION(nsnull!=mContent, "bad state -- null content for frame");
  nsresult rv=NS_OK;
  
  const nsStyleVisibility* groupVis = GetStyleVisibility();
  bool collapseGroup = (NS_STYLE_VISIBILITY_COLLAPSE == groupVis->mVisible);
  if (collapseGroup) {
    nsTableFrame* tableFrame = nsTableFrame::GetTableFrame(this);
    tableFrame->SetNeedToCollapse(true);
  }
  // for every content child that (is a column thingy and does not already have a frame)
  // create a frame and adjust it's style
  
  for (nsIFrame *kidFrame = mFrames.FirstChild(); kidFrame;
       kidFrame = kidFrame->GetNextSibling()) {
    // Give the child frame a chance to reflow, even though we know it'll have 0 size
    nsHTMLReflowMetrics kidSize;
    nsHTMLReflowState kidReflowState(aPresContext, aReflowState, kidFrame,
                                     nsSize(0,0));

    nsReflowStatus status;
    ReflowChild(kidFrame, aPresContext, kidSize, kidReflowState, 0, 0, 0, status);
    FinishReflowChild(kidFrame, aPresContext, nsnull, kidSize, 0, 0, 0);
  }

  aDesiredSize.width=0;
  aDesiredSize.height=0;
  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return rv;
}

NS_IMETHODIMP nsFileControlFrame::Reflow(nsPresContext*          aPresContext, 
                                         nsHTMLReflowMetrics&     aDesiredSize,
                                         const nsHTMLReflowState& aReflowState, 
                                         nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsFileControlFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);

  aStatus = NS_FRAME_COMPLETE;

  if (mState & NS_FRAME_FIRST_REFLOW) {
    mTextFrame = GetTextControlFrame(aPresContext, this);
    NS_ENSURE_TRUE(mTextFrame, NS_ERROR_UNEXPECTED);
    if (mCachedState) {
      mTextFrame->SetFormProperty(nsGkAtoms::value, *mCachedState);
      delete mCachedState;
      mCachedState = nsnull;
    }
  }

  // The Areaframe takes care of all our reflow
  return nsAreaFrame::Reflow(aPresContext, aDesiredSize, aReflowState,
                             aStatus);
}

/* virtual */ void
nsRubyTextContainerFrame::Reflow(nsPresContext* aPresContext,
                                 nsHTMLReflowMetrics& aDesiredSize,
                                 const nsHTMLReflowState& aReflowState,
                                 nsReflowStatus& aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsRubyTextContainerFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);

  // All rt children have already been reflowed. All we need to do is clean up
  // the line layout.

  aStatus = NS_FRAME_COMPLETE;
  mozilla::WritingMode lineWM = aReflowState.mLineLayout->GetWritingMode();
  mozilla::WritingMode frameWM = aReflowState.GetWritingMode();
  mozilla::LogicalMargin borderPadding =
    aReflowState.ComputedLogicalBorderPadding();

  aDesiredSize.ISize(lineWM) = mISize;
  nsLayoutUtils::SetBSizeFromFontMetrics(this, aDesiredSize, aReflowState,
                                         borderPadding, lineWM, frameWM);

  nscoord bsize = aDesiredSize.BSize(lineWM);
  if (!mLines.empty()) {
    // Okay to use BlockStartAscent because it has just been correctly set by
    // nsLayoutUtils::SetBSizeFromFontMetrics.
    mLines.begin()->SetLogicalAscent(aDesiredSize.BlockStartAscent());
    mLines.begin()->SetBounds(aReflowState.GetWritingMode(), 0, 0, mISize,
                              bsize, mISize);
  }

  if (mLineLayout) {
    mLineLayout->EndLineReflow();
    mLineLayout = nullptr;
  }
}

nsresult 
nsPageBreakFrame::Reflow(nsPresContext*           aPresContext,
                         nsHTMLReflowMetrics&     aDesiredSize,
                         const nsHTMLReflowState& aReflowState,
                         nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsPageBreakFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);

  // Override reflow, since we don't want to deal with what our
  // computed values are.
  aDesiredSize.width = GetIntrinsicWidth();
  aDesiredSize.height = (aReflowState.availableHeight == NS_UNCONSTRAINEDSIZE ?
                         0 : aReflowState.availableHeight);
  // round the height down to the nearest pixel
  aDesiredSize.height -=
    aDesiredSize.height % nsPresContext::CSSPixelsToAppUnits(1);

  // Note: not using NS_FRAME_FIRST_REFLOW here, since it's not clear whether
  // DidReflow will always get called before the next Reflow() call.
  mHaveReflowed = PR_TRUE;
  aStatus = NS_FRAME_COMPLETE; 
  return NS_OK;
}

NS_IMETHODIMP
SpacerFrame::Reflow(nsPresContext*          aPresContext,
                    nsHTMLReflowMetrics&     aMetrics,
                    const nsHTMLReflowState& aReflowState,
                    nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("SpacerFrame", aReflowState.reason);
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
  aStatus = NS_FRAME_COMPLETE;

  // By default, we have no area
  aMetrics.width = 0;
  aMetrics.height = 0;
  aMetrics.ascent = 0;
  aMetrics.descent = 0;

  const nsStylePosition* position = GetStylePosition();

  PRUint8 type = GetType();
  switch (type) {
  case TYPE_WORD:
    break;

  case TYPE_LINE:
    aStatus = NS_INLINE_LINE_BREAK_AFTER(NS_FRAME_COMPLETE);
    if (eStyleUnit_Coord == position->mHeight.GetUnit()) {
      aMetrics.width = position->mHeight.GetCoordValue();
    }
    aMetrics.ascent = aMetrics.height;
    break;

  case TYPE_IMAGE:
    // width
    nsStyleUnit unit = position->mWidth.GetUnit();
    if (eStyleUnit_Coord == unit) {
      aMetrics.width = position->mWidth.GetCoordValue();
    }
    else if (eStyleUnit_Percent == unit) 
    {
      if (NS_UNCONSTRAINEDSIZE != aReflowState.availableWidth)
      {
        float factor = position->mWidth.GetPercentValue();
        aMetrics.width = NSToCoordRound (factor * aReflowState.availableWidth);
      }
    }

    // height
    unit = position->mHeight.GetUnit();
    if (eStyleUnit_Coord == unit) {
      aMetrics.height = position->mHeight.GetCoordValue();
    }
    else if (eStyleUnit_Percent == unit) 
    {
      if (NS_UNCONSTRAINEDSIZE != aReflowState.availableHeight)
      {
        float factor = position->mHeight.GetPercentValue();
        aMetrics.width = NSToCoordRound (factor * aReflowState.availableHeight);
      }
    }
    // accent
    aMetrics.ascent = aMetrics.height;
    break;
  }

  if (aMetrics.width || aMetrics.height) {
    // Make sure that the other dimension is non-zero
    if (!aMetrics.width) aMetrics.width = 1;
    if (!aMetrics.height) aMetrics.height = 1;
  }

  if (aMetrics.mComputeMEW) {
    aMetrics.SetMEWToActualWidth(aReflowState.mStylePosition->mWidth.GetUnit());
  }

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
  return NS_OK;
}

NS_IMETHODIMP
nsFirstLetterFrame::Reflow(nsPresContext*          aPresContext,
                           nsHTMLReflowMetrics&     aMetrics,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aReflowStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsFirstLetterFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aReflowStatus);
  nsresult rv = NS_OK;

  // Grab overflow list
  DrainOverflowFrames(aPresContext);

  nsIFrame* kid = mFrames.FirstChild();

  // Setup reflow state for our child
  nsSize availSize(aReflowState.availableWidth, aReflowState.availableHeight);
  const nsMargin& bp = aReflowState.mComputedBorderPadding;
  nscoord lr = bp.left + bp.right;
  nscoord tb = bp.top + bp.bottom;
  NS_ASSERTION(availSize.width != NS_UNCONSTRAINEDSIZE,
               "should no longer use unconstrained widths");
  availSize.width -= lr;
  if (NS_UNCONSTRAINEDSIZE != availSize.height) {
    availSize.height -= tb;
  }

  // Reflow the child
  if (!aReflowState.mLineLayout) {
    // When there is no lineLayout provided, we provide our own. The
    // only time that the first-letter-frame is not reflowing in a
    // line context is when its floating.
    nsHTMLReflowState rs(aPresContext, aReflowState, kid, availSize);
    nsLineLayout ll(aPresContext, nsnull, &aReflowState, nsnull);
    ll.BeginLineReflow(bp.left, bp.top, availSize.width, NS_UNCONSTRAINEDSIZE,
                       PR_FALSE, PR_TRUE);
    rs.mLineLayout = ≪
    ll.SetFirstLetterStyleOK(PR_TRUE);

    kid->WillReflow(aPresContext);
    kid->Reflow(aPresContext, aMetrics, rs, aReflowStatus);

    ll.EndLineReflow();
  }
  else {
    // Pretend we are a span and reflow the child frame
    nsLineLayout* ll = aReflowState.mLineLayout;
    PRBool        pushedFrame;

    NS_ASSERTION(ll->GetFirstLetterStyleOK() || GetPrevInFlow(),
                 "First-in-flow first-letter should have first-letter style enabled in nsLineLayout!");
    ll->BeginSpan(this, &aReflowState, bp.left, availSize.width);
    ll->ReflowFrame(kid, aReflowStatus, &aMetrics, pushedFrame);
    ll->EndSpan(this);
  }

  // Place and size the child and update the output metrics
  kid->SetRect(nsRect(bp.left, bp.top, aMetrics.width, aMetrics.height));
  kid->FinishAndStoreOverflow(&aMetrics);
  kid->DidReflow(aPresContext, nsnull, NS_FRAME_REFLOW_FINISHED);

  aMetrics.width += lr;
  aMetrics.height += tb;
  aMetrics.ascent += bp.top;
  mBaseline = aMetrics.ascent;

  // Ensure that the overflow rect contains the child textframe's overflow rect.
  // Note that if this is floating, the overline/underline drawable area is in
  // the overflow rect of the child textframe.
  aMetrics.mOverflowArea.UnionRect(aMetrics.mOverflowArea,
                           nsRect(0, 0, aMetrics.width, aMetrics.height));
  ConsiderChildOverflow(aMetrics.mOverflowArea, kid);

  // Create a continuation or remove existing continuations based on
  // the reflow completion status.
  if (NS_FRAME_IS_COMPLETE(aReflowStatus)) {
    if (aReflowState.mLineLayout) {
      aReflowState.mLineLayout->SetFirstLetterStyleOK(PR_FALSE);
    }
    nsIFrame* kidNextInFlow = kid->GetNextInFlow();
    if (kidNextInFlow) {
      // Remove all of the childs next-in-flows
      static_cast<nsContainerFrame*>(kidNextInFlow->GetParent())
        ->DeleteNextInFlowChild(aPresContext, kidNextInFlow);
    }
  }
  else {
    // Create a continuation for the child frame if it doesn't already
    // have one.
    nsIFrame* nextInFlow;
    rv = CreateNextInFlow(aPresContext, this, kid, nextInFlow);
    if (NS_FAILED(rv)) {
      return rv;
    }

    // And then push it to our overflow list
    if (nextInFlow) {
      kid->SetNextSibling(nsnull);
      SetOverflowFrames(aPresContext, nextInFlow);
    }
//.........這裏部分代碼省略.........

void
nsLeafBoxFrame::Reflow(nsPresContext*   aPresContext,
                     nsHTMLReflowMetrics&     aDesiredSize,
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus)
{
  // This is mostly a copy of nsBoxFrame::Reflow().
  // We aren't able to share an implementation because of the frame
  // class hierarchy.  If you make changes here, please keep
  // nsBoxFrame::Reflow in sync.

  DO_GLOBAL_REFLOW_COUNT("nsLeafBoxFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);

  NS_ASSERTION(aReflowState.ComputedWidth() >=0 &&
               aReflowState.ComputedHeight() >= 0, "Computed Size < 0");

#ifdef DO_NOISY_REFLOW
  printf("\n-------------Starting LeafBoxFrame Reflow ----------------------------\n");
  printf("%p ** nsLBF::Reflow %d R: ", this, myCounter++);
  switch (aReflowState.reason) {
    case eReflowReason_Initial:
      printf("Ini");break;
    case eReflowReason_Incremental:
      printf("Inc");break;
    case eReflowReason_Resize:
      printf("Rsz");break;
    case eReflowReason_StyleChange:
      printf("Sty");break;
    case eReflowReason_Dirty:
      printf("Drt ");
      break;
    default:printf("<unknown>%d", aReflowState.reason);break;
  }
  
  printSize("AW", aReflowState.AvailableWidth());
  printSize("AH", aReflowState.AvailableHeight());
  printSize("CW", aReflowState.ComputedWidth());
  printSize("CH", aReflowState.ComputedHeight());

  printf(" *\n");

#endif

  aStatus = NS_FRAME_COMPLETE;

  // create the layout state
  nsBoxLayoutState state(aPresContext, aReflowState.rendContext);

  nsSize computedSize(aReflowState.ComputedWidth(),aReflowState.ComputedHeight());

  nsMargin m;
  m = aReflowState.ComputedPhysicalBorderPadding();

  //GetBorderAndPadding(m);

  // this happens sometimes. So lets handle it gracefully.
  if (aReflowState.ComputedHeight() == 0) {
    nsSize minSize = GetMinSize(state);
    computedSize.height = minSize.height - m.top - m.bottom;
  }

  nsSize prefSize(0,0);

  // if we are told to layout intrinic then get our preferred size.
  if (computedSize.width == NS_INTRINSICSIZE || computedSize.height == NS_INTRINSICSIZE) {
     prefSize = GetPrefSize(state);
     nsSize minSize = GetMinSize(state);
     nsSize maxSize = GetMaxSize(state);
     prefSize = BoundsCheck(minSize, prefSize, maxSize);
  }

  // get our desiredSize
  if (aReflowState.ComputedWidth() == NS_INTRINSICSIZE) {
    computedSize.width = prefSize.width;
  } else {
    computedSize.width += m.left + m.right;
  }

  if (aReflowState.ComputedHeight() == NS_INTRINSICSIZE) {
    computedSize.height = prefSize.height;
  } else {
    computedSize.height += m.top + m.bottom;
  }

  // handle reflow state min and max sizes
  // XXXbz the width handling here seems to be wrong, since
  // mComputedMin/MaxWidth is a content-box size, whole
  // computedSize.width is a border-box size...
  if (computedSize.width > aReflowState.ComputedMaxWidth())
    computedSize.width = aReflowState.ComputedMaxWidth();

  if (computedSize.width < aReflowState.ComputedMinWidth())
    computedSize.width = aReflowState.ComputedMinWidth();

  // Now adjust computedSize.height for our min and max computed
  // height.  The only problem is that those are content-box sizes,
  // while computedSize.height is a border-box size.  So subtract off
  // m.TopBottom() before adjusting, then readd it.
  computedSize.height = std::max(0, computedSize.height - m.TopBottom());
//.........這裏部分代碼省略.........