Hittest for RootInlineBox/InlineFlowBox should take care of border-radius.

Source/core/layout/line/InlineFlowBox.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 994 matching lines @@
             }
         }
     }
     // Check any culled ancestor of the final children tested.
     while (culledParent && culledParent != layoutObject()) {
         if (culledParent->isLayoutInline() && toLayoutInline(culledParent)->hitTestCulledInline(request, result, locationInContainer, accumulatedOffset))
             return true;
         culledParent = culledParent->parent();
     }
 
+    if (layoutObject().style()->hasBorderRadius()) {
+        LayoutRect borderRect = logicalFrameRect();
+        borderRect.moveBy(accumulatedOffset);
+        FloatRoundedRect border = layoutObject().style()->getRoundedBorderFor(borderRect, includeLogicalLeftEdge(), includeLogicalRightEdge());
+        if (!locationInContainer.intersects(border))
+            return false;
+    }
+
     // Now check ourselves. Pixel snap hit testing.
     LayoutRect frameRect(roundedFrameRect());
     LayoutUnit minX = frameRect.x();
     LayoutUnit minY = frameRect.y();
     LayoutUnit width = frameRect.width();
     LayoutUnit height = frameRect.height();
 
     // Constrain our hit testing to the line top and bottom if necessary.
     bool noQuirksMode = layoutObject().document().inNoQuirksMode();
     if (!noQuirksMode && !hasTextChildren() && !(descendantsHaveSameLineHeightAndBaseline() && hasTextDescendants())) {
@@ skipping 274 matching lines @@
         ASSERT(child->prevOnLine() == prev);
         prev = child;
     }
     ASSERT(prev == m_lastChild);
 #endif
 }
 
 #endif
 
 } // namespace blink