Add infrastructure for partial layouts

Source/core/rendering/RenderRuby.h

Index: Source/core/rendering/RenderRuby.h
diff --git a/Source/core/rendering/RenderRuby.h b/Source/core/rendering/RenderRuby.h
index e254b05d0380a44d6dd89cfb0526633e518b5fb9..5ffe327e6bc113c825cc8f5fe3023dd1965d0674 100644
--- a/Source/core/rendering/RenderRuby.h
+++ b/Source/core/rendering/RenderRuby.h
@@ -65,6 +65,7 @@ protected:
 private:
     virtual bool isRuby() const { return true; }
     virtual const char* renderName() const { return "RenderRuby (inline)"; }
+    virtual bool supportsPartialLayout() const OVERRIDE { return false; }
     virtual bool createsAnonymousWrapper() const { return true; }
     virtual void removeLeftoverAnonymousBlock(RenderBlock*) { ASSERT_NOT_REACHED(); }
 };
@@ -84,6 +85,7 @@ protected:
 private:
     virtual bool isRuby() const { return true; }
     virtual const char* renderName() const { return "RenderRuby (block)"; }
+    virtual bool supportsPartialLayout() const OVERRIDE { return false; }
     virtual bool createsAnonymousWrapper() const { return true; }
     virtual void removeLeftoverAnonymousBlock(RenderBlock*) { ASSERT_NOT_REACHED(); }
 };