This affects the slow-path result of positionFromPaintInvalidationBacking calculation, but it seems not to cause any bugs in paint invalidation because we are using the results just for movement detection by comparing the old and new values. It doesn't matter if both the old value and new value miss offset above the containing frame.

Seems easy to fix.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/24787f3652aacb653940d81650fce15f70188494

commit 24787f3652aacb653940d81650fce15f70188494
Author: chrishtr <chrishtr@chromium.org>
Date: Sat Aug 13 00:57:36 2016

Pass MapCoordinatesFlags through SVGLayoutSupport::mapLocalToAncestor

BUG= 597745 

Review-Url: https://codereview.chromium.org/2241833002
Cr-Commit-Position: refs/heads/master@{#411838}

[modify] https://crrev.com/24787f3652aacb653940d81650fce15f70188494/third_party/WebKit/Source/core/layout/PaintInvalidationState.cpp
[modify] https://crrev.com/24787f3652aacb653940d81650fce15f70188494/third_party/WebKit/Source/core/layout/svg/LayoutSVGBlock.cpp
[modify] https://crrev.com/24787f3652aacb653940d81650fce15f70188494/third_party/WebKit/Source/core/layout/svg/LayoutSVGInline.cpp
[modify] https://crrev.com/24787f3652aacb653940d81650fce15f70188494/third_party/WebKit/Source/core/layout/svg/LayoutSVGModelObject.cpp
[modify] https://crrev.com/24787f3652aacb653940d81650fce15f70188494/third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.cpp
[modify] https://crrev.com/24787f3652aacb653940d81650fce15f70188494/third_party/WebKit/Source/core/layout/svg/SVGLayoutSupport.h