Add offset contributed to sticky position box rect by location containers

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 2220 matching lines @@
                                0);
     transform = perspectiveMatrix * transform;
     transform.translateRight3d(perspectiveOrigin.x(), perspectiveOrigin.y(), 0);
   }
 }
 
 FloatQuad LayoutObject::localToAncestorQuad(
     const FloatQuad& localQuad,
     const LayoutBoxModelObject* ancestor,
     MapCoordinatesFlags mode) const {
+  return localToAncestorQuadWithoutTransforms(localQuad, ancestor,
+                                              mode | UseTransforms);
+}
+
+FloatQuad LayoutObject::localToAncestorQuadWithoutTransforms(

[Xianzhu, 2017/01/24 22:53:11]

I like the direction of the new code, but
  localAncestorQuadWithoutTransforms( ...  UseTransforms)
looks weird.

How about adding 
  mapLocalToAncestorQuadInternal() which contains line 2249-2258, and

... ::localToAncestorQuad(...) {
  return mapLocalToAncestorQuadInternal(  ... | UseTransforms);
}

... ::localToAncestorQuadWithoutTransforms(...) {
  DCHECK(!(mode & UseTransforms));
  return mapLocalToAncestorQuadInternal(...);
}

[flackr, 2017/01/25 13:23:24]

Done.

+    const FloatQuad& localQuad,
+    const LayoutBoxModelObject* ancestor,
+    MapCoordinatesFlags mode) const {
   // Track the point at the center of the quad's bounding box. As
   // mapLocalToAncestor() calls offsetFromContainer(), it will use that point
   // as the reference point to decide which column's transform to apply in
   // multiple-column blocks.
   TransformState transformState(TransformState::ApplyTransformDirection,
                                 localQuad.boundingBox().center(), localQuad);
-  mapLocalToAncestor(ancestor, transformState,
-                     mode | ApplyContainerFlip | UseTransforms);
+  mapLocalToAncestor(ancestor, transformState, mode | ApplyContainerFlip);
   transformState.flatten();
 
   return transformState.lastPlanarQuad();
 }
 
 FloatPoint LayoutObject::localToAncestorPoint(
     const FloatPoint& localPoint,
     const LayoutBoxModelObject* ancestor,
     MapCoordinatesFlags mode) const {
   TransformState transformState(TransformState::ApplyTransformDirection,
@@ skipping 1219 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->parent())
       root = root->parent();
     root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif