Center dialogs before computing overflow.

Source/core/rendering/RenderBlockFlow.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/rendering/RenderBlockFlow.h"
 
 #include "core/accessibility/AXObjectCache.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
+#include "core/html/HTMLDialogElement.h"
 #include "core/rendering/HitTestLocation.h"
 #include "core/rendering/RenderFlowThread.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderMultiColumnFlowThread.h"
 #include "core/rendering/RenderPagedFlowThread.h"
 #include "core/rendering/RenderText.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/TextAutosizer.h"
 #include "core/rendering/line/LineWidth.h"
 #include "core/rendering/svg/SVGTextRunRenderingContext.h"
@@ skipping 327 matching lines @@
         bool hasVisibleContent = style()->visibility() == VISIBLE;
         if (!hasVisibleContent) {
             RenderLayer* layer = enclosingLayer();
             layer->updateDescendantDependentFlags();
             hasVisibleContent = layer->hasVisibleContent();
         }
         if (hasVisibleContent)
             setShouldInvalidateOverflowForPaint(true);
     }
 
+    if (isHTMLDialogElement(node()) && isOutOfFlowPositioned())
+        positionDialog();
+
     clearNeedsLayout();
 }
 
 inline bool RenderBlockFlow::layoutBlockFlow(bool relayoutChildren, LayoutUnit &pageLogicalHeight, SubtreeLayoutScope& layoutScope)
 {
     LayoutUnit oldLeft = logicalLeft();
     bool logicalWidthChanged = updateLogicalWidthAndColumnWidth();
     relayoutChildren |= logicalWidthChanged;
 
     rebuildFloatsFromIntruding();
@@ skipping 2509 matching lines @@
 
 RenderBlockFlow::RenderBlockFlowRareData& RenderBlockFlow::ensureRareData()
 {
     if (m_rareData)
         return *m_rareData;
 
     m_rareData = adoptPtrWillBeNoop(new RenderBlockFlowRareData(this));
     return *m_rareData;
 }
 
+void RenderBlockFlow::positionDialog()
+{
+    HTMLDialogElement* dialog = toHTMLDialogElement(node());
+    if (dialog->centeringMode() == HTMLDialogElement::NotCentered)
+        return;
+
+    bool canCenterDialog = (style()->position() == AbsolutePosition || style()->position() == FixedPosition)
+        && style()->hasAutoTopAndBottom();
+
+    if (dialog->centeringMode() == HTMLDialogElement::Centered) {
+        if (canCenterDialog)
+            setY(dialog->centeredPosition());
+        return;
+    }
+
+    ASSERT(dialog->centeringMode() == HTMLDialogElement::NeedsCentering);
+    if (!canCenterDialog) {
+        dialog->setNotCentered();
+        return;
+    }
+
+    FrameView* frameView = document().view();
+    LayoutUnit top = (style()->position() == FixedPosition) ? 0 : frameView->scrollOffset().height();
+    int visibleHeight = frameView->visibleContentRect(IncludeScrollbars).height();
+    if (height() < visibleHeight)
+        top += (visibleHeight - height()) / 2;
+    setY(top);
+    dialog->setCentered(top);
+}
+
 } // namespace blink