Remove frame flattening support as Chromium has no intention of using it

Source/core/rendering/RenderIFrame.cpp

 /*
  * Copyright (C) 2010 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 19 matching lines @@
 #include "FrameView.h"
 #include "HTMLIFrameElement.h"
 #include "HTMLNames.h"
 #include "Page.h"
 #include "RenderView.h"
 #include "Settings.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
-    
+
 RenderIFrame::RenderIFrame(Element* element)
-    : RenderFrameBase(element)
+    : RenderPart(element)
 {
 }
 
 bool RenderIFrame::shouldComputeSizeAsReplaced() const
 {
     // When we're seamless, we use normal block/box sizing code except when inline.
     return !isSeamless();
 }
 
 bool RenderIFrame::isInlineBlockOrInlineTable() const
 {
     return isSeamless() && isInline();
 }
 
 LayoutUnit RenderIFrame::minPreferredLogicalWidth() const
 {
     if (!isSeamless())
-        return RenderFrameBase::minPreferredLogicalWidth();
+        return RenderPart::minPreferredLogicalWidth();
 
     RenderView* childRoot = contentRootRenderer();
     if (!childRoot)
         return 0;
 
     return childRoot->minPreferredLogicalWidth() + borderAndPaddingLogicalWidth();
 }
 
 LayoutUnit RenderIFrame::maxPreferredLogicalWidth() const
 {
     if (!isSeamless())
-        return RenderFrameBase::maxPreferredLogicalWidth();
+        return RenderPart::maxPreferredLogicalWidth();
 
     RenderView* childRoot = contentRootRenderer();
     if (!childRoot)
         return 0;
 
     return childRoot->maxPreferredLogicalWidth() + borderAndPaddingLogicalWidth();
 }
 
 bool RenderIFrame::isSeamless() const
 {
     return node() && node()->hasTagName(iframeTag) && static_cast<HTMLIFrameElement*>(node())->shouldDisplaySeamlessly();
 }
 
 bool RenderIFrame::requiresLayer() const
 {
-    return RenderFrameBase::requiresLayer() || style()->resize() != RESIZE_NONE;
+    return RenderPart::requiresLayer() || style()->resize() != RESIZE_NONE;
 }
 
 RenderView* RenderIFrame::contentRootRenderer() const
 {
     // FIXME: Is this always a valid cast? What about plugins?
     ASSERT(!widget() || widget()->isFrameView());
     FrameView* childFrameView = toFrameView(widget());
     return childFrameView ? childFrameView->frame()->contentRenderer() : 0;
 }
 
-bool RenderIFrame::flattenFrame() const
-{
-    if (!node() || !node()->hasTagName(iframeTag))
-        return false;
-
-    HTMLIFrameElement* element = static_cast<HTMLIFrameElement*>(node());
-    Frame* frame = element->document()->frame();
-
-    if (isSeamless())
-        return false; // Seamless iframes are already "flat", don't try to flatten them.
-
-    bool enabled = frame && frame->settings() && frame->settings()->frameFlatteningEnabled();
-
-    if (!enabled || !frame->page())
-        return false;
-
-    if (style()->width().isFixed() && style()->height().isFixed()) {
-        // Do not flatten iframes with scrolling="no".
-        if (element->scrollingMode() == ScrollbarAlwaysOff)
-            return false;
-        if (style()->width().value() <= 0 || style()->height().value() <= 0)
-            return false;
-    }
-
-    // Do not flatten offscreen inner frames during frame flattening, as flattening might make them visible.
-    IntRect boundingRect = absoluteBoundingBoxRectIgnoringTransforms();
-    return boundingRect.maxX() > 0 && boundingRect.maxY() > 0;
-}
-
 void RenderIFrame::layoutSeamlessly()
 {
     updateLogicalWidth();
     // FIXME: Containers set their height to 0 before laying out their kids (as we're doing here)
     // however, this causes FrameView::layout() to add vertical scrollbars, incorrectly inflating
     // the resulting contentHeight(). We'll need to make FrameView::layout() smarter.
     setLogicalHeight(0);
     updateWidgetPosition(); // Tell the Widget about our new width/height (it will also layout the child document).
 
     // Laying out our kids is normally responsible for adjusting our height, so we set it here.
@@ skipping 17 matching lines @@
     StackStats::LayoutCheckPoint layoutCheckPoint;
     ASSERT(needsLayout());
 
     if (isSeamless()) {
         layoutSeamlessly();
         // Do not return so as to share the layer and overflow updates below.
     } else {
         updateLogicalWidth();
         // No kids to layout as a replaced element.
         updateLogicalHeight();
-
-        if (flattenFrame())
-            layoutWithFlattening(style()->width().isFixed(), style()->height().isFixed());
     }
 
     m_overflow.clear();
     addVisualEffectOverflow();
     updateLayerTransform();
 
     setNeedsLayout(false);
 }
 
 }