[SPInvalidation] Fix fixed-position printing

third_party/WebKit/Source/core/paint/PaintLayerPainter.h

Index: third_party/WebKit/Source/core/paint/PaintLayerPainter.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerPainter.h b/third_party/WebKit/Source/core/paint/PaintLayerPainter.h
index 3e9f3494a226e09c42c396330d45fc9bcf672d08..86dbcc103d62e8add3f9e6ec7a205c3b9fdc78f5 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerPainter.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayerPainter.h
@@ -56,9 +56,9 @@ class CORE_EXPORT PaintLayerPainter {
  private:
   enum ClipState { HasNotClipped, HasClipped };
 
-  bool collectPaintFragmentsForPaginatedFixedPosition(
-      const PaintLayerPaintingInfo&,
-      PaintLayerFragments&);
+  inline bool isFixedPositionObjectInPagedMedia();
+  void repeatFixedPositionObjectInPages(const PaintLayerPaintingInfo&,

[chrishtr, 2017/01/03 18:53:10]

The input for repeatFixedPositionObjectInPages must be a single
fragment that is then repeated. How about changing the signature
to enforce that? e.g. input is PaintLayerFragment and output is
PaintLayerFragments.

Also, this fixed-pos code seems pretty hacky (not your fault, it
was like that before). It would be good to fold it into
collectFragments somehow, add a TODO?

[Xianzhu, 2017/01/03 19:54:42]

Done.
Done.

Actually I reviewed the original change adding the fixed-position hack. For now
the hack (instead of folded into collectFragment) it's still needed because of
the specialty of the transformed path.

+                                        PaintLayerFragments&);
 
   PaintResult paintLayerContentsCompositingAllPhases(
       GraphicsContext&,