[repaint-after-layout] Only repaint SVG root element when needed.

Source/core/rendering/svg/RenderSVGRoot.cpp

Index: Source/core/rendering/svg/RenderSVGRoot.cpp
diff --git a/Source/core/rendering/svg/RenderSVGRoot.cpp b/Source/core/rendering/svg/RenderSVGRoot.cpp
index 0e181b49e1f54b88ade56fab23a9e6f900aa81b7..5f0875bdfc122bc3a394ccdef7089bad1409d187 100644
--- a/Source/core/rendering/svg/RenderSVGRoot.cpp
+++ b/Source/core/rendering/svg/RenderSVGRoot.cpp
@@ -195,12 +195,11 @@ void RenderSVGRoot::layout()
 {
     ASSERT(needsLayout());
 
-    LayoutRectRecorder recorder(*this);
-
     // Arbitrary affine transforms are incompatible with LayoutState.
     LayoutStateDisabler layoutStateDisabler(*this);
 
     bool needsLayout = selfNeedsLayout();
+    LayoutRectRecorder recorder(*this, !(checkForRepaint() && needsLayout));

[esprehn, 2014/03/21 18:17:29]

Can you propagate the ! through the statement? It's much easier to read that
way.

!checkForRepaint() || !needsLayout()

[dsinclair, 2014/03/24 14:46:28]

The flag was badly named, so I inverted the meaning and made this just
checkForRepaint() && needsLayout()

     LayoutRepainter repainter(*this, checkForRepaintDuringLayout() && needsLayout);
 
     LayoutSize oldSize = size();