Fix under-invalidation on SVG shape/image resize in subpixels

third_party/WebKit/Source/core/layout/svg/LayoutSVGShape.cpp

Index: third_party/WebKit/Source/core/layout/svg/LayoutSVGShape.cpp
diff --git a/third_party/WebKit/Source/core/layout/svg/LayoutSVGShape.cpp b/third_party/WebKit/Source/core/layout/svg/LayoutSVGShape.cpp
index 266baa1a00c48b4f8aab03fb8e9124c762c500c4..571f0d4e2a8859792260299a3414ae6630b6f48f 100644
--- a/third_party/WebKit/Source/core/layout/svg/LayoutSVGShape.cpp
+++ b/third_party/WebKit/Source/core/layout/svg/LayoutSVGShape.cpp
@@ -184,7 +184,10 @@ void LayoutSVGShape::layout() {
   // feeds into the paint invalidation rect - so we need to call it for both
   // the shape-update and the bounds-update flag, since .

[pdr., 2016/10/31 20:49:05]

Not your fault (https://crrev.com/fe8421b9573ca696e596248811edf0a5d23fc191) but
can you fix this broken comment:
// the shape-update and the bounds-update flag.

(remove ", since ")

[Xianzhu, 2016/10/31 22:10:30]

The fix is in https://codereview.chromium.org/2465983002/ :)

   if (m_needsShapeUpdate || m_needsBoundariesUpdate) {
+    FloatRect oldStrokeBoundingBox = strokeBoundingBox();

[pdr., 2016/10/31 20:49:05]

Are you using the stroke bounding box because it includes the object bounding
box too?

If so, could you add that as a comment?
// We use the stroke bounding box because it includes both the stroke and the
object bounding box.

[Xianzhu, 2016/10/31 22:10:30]

Used strokeBoundingBox just because it is used for paint invalidation below.
This should be correct[1] but using objectBoundingBox is more intuitive. Changed
to objectBoundingBox.

[1] It's correct because a) it catches object bounding box change in most cases,
b) if object bounding box changes but other changes (e.g. stroke width change)
happen to make stroke bounding box not change, other changes will cause paint
invalidation.

     updateShapeFromElement();
+    if (oldStrokeBoundingBox != strokeBoundingBox())
+      setShouldDoFullPaintInvalidation();
     m_needsShapeUpdate = false;
 
     m_paintInvalidationBoundingBox = strokeBoundingBox();