Don't paint below image's baseline unless it is selected.

Source/core/rendering/RenderReplaced.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011-2012. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 557 matching lines @@
     if (root.block().style()->isHorizontalWritingMode())
         return LayoutRect(0, newLogicalTop, width(), root.selectionHeight());
     return LayoutRect(newLogicalTop, 0, root.selectionHeight(), height());
 }
 
 void RenderReplaced::setSelectionState(SelectionState state)
 {
     // The selection state for our containing block hierarchy is updated by the base class call.
     RenderBox::setSelectionState(state);
 
-    if (inlineBoxWrapper() && canUpdateSelectionOnRootLineBoxes())
+    if (!inlineBoxWrapper())
+        return;
+
+    // We only include the space below the baseline in our layer's cached repaint rect if the
+    // image is selected. Since the selection state has changed update the rect.
+    if (hasLayer())
+        layer()->repainter().computeRepaintRects(containerForRepaint());

[Julien - ping for review, 2014/05/02 00:23:35]

I would expect this to fail with repaint-after-layout as we disable
RenderLayerRepainter.

In repaint-after-layout, you need to update the previous repaint rectangle (and
the previous position from the repaint container).

[rhogan, 2014/05/02 15:36:27]

If the layer-based repainter goes away then it will just get the correct rect
from clippedOverflowRectForRepaint() in
RenderObject::repaintAfterLayoutIfNeeded().

If I've misunderstood you could you point me in the right direction though?

+
+    if (canUpdateSelectionOnRootLineBoxes())
         inlineBoxWrapper()->root().setHasSelectedChildren(isSelected());
 }
 
 bool RenderReplaced::isSelected() const
 {
     SelectionState s = selectionState();
     if (s == SelectionNone)
         return false;
     if (s == SelectionInside)
         return true;
 
     int selectionStart, selectionEnd;
     selectionStartEnd(selectionStart, selectionEnd);
     if (s == SelectionStart)
         return selectionStart == 0;
 
     int end = node()->hasChildren() ? node()->countChildren() : 1;
     if (s == SelectionEnd)
         return selectionEnd == end;
     if (s == SelectionBoth)
         return selectionStart == 0 && selectionEnd == end;
 
     ASSERT(0);
     return false;
 }
 
-LayoutRect RenderReplaced::clippedOverflowRectForRepaint(const RenderLayerModelObject* repaintContainer) const
-{
-    if (style()->visibility() != VISIBLE && !enclosingLayer()->hasVisibleContent())
-        return LayoutRect();
-
-    // The selectionRect can project outside of the overflowRect, so take their union
-    // for repainting to avoid selection painting glitches.
-    LayoutRect r = unionRect(localSelectionRect(false), visualOverflowRect());
-
-    RenderView* v = view();
-    if (!RuntimeEnabledFeatures::repaintAfterLayoutEnabled() && v) {
-        // FIXME: layoutDelta needs to be applied in parts before/after transforms and
-        // repaint containers. https://bugs.webkit.org/show_bug.cgi?id=23308
-        r.move(v->layoutDelta());
-    }
-
-    computeRectForRepaint(repaintContainer, r);
-    return r;
 }
-
-}