Avoid using forced layout to trigger paint invalidation for SVG containers

third_party/WebKit/Source/platform/transforms/AffineTransform.cpp

Index: third_party/WebKit/Source/platform/transforms/AffineTransform.cpp
diff --git a/third_party/WebKit/Source/platform/transforms/AffineTransform.cpp b/third_party/WebKit/Source/platform/transforms/AffineTransform.cpp
index 5bfbd0e2d4c6727a750fa9f35f5394755833ddee..3f08a99d8293c271b4edd0f4c4b327cbfcf434be 100644
--- a/third_party/WebKit/Source/platform/transforms/AffineTransform.cpp
+++ b/third_party/WebKit/Source/platform/transforms/AffineTransform.cpp
@@ -68,14 +68,24 @@ bool AffineTransform::isIdentity() const
          && m_transform[4] == 0 && m_transform[5] == 0);
 }
 
+double AffineTransform::xScaleSquared() const
+{
+    return m_transform[0] * m_transform[0] + m_transform[1] * m_transform[1];

[pdr., 2016/06/15 12:15:17]

A little out of scope for this patch, just noting because it seems odd: wouldn't
xScale be m_transform[0] and yScale be m_transform[3]? I.e., no need to include
the sheer components? Squaring could also introduce an edge-case bug when the
scale value is negative.

[fs, 2016/06/15 22:10:33]

It's more like "x/y basis magnitude" than "x/y scale". This is what's being used
"downstream" in clients though. (And I think the shearing component will affect
non-scaling stroke?) Similarly for negative scales (== flips), since those won't
affect the size of the descendants.

+}
+
 double AffineTransform::xScale() const
 {
-    return sqrt(m_transform[0] * m_transform[0] + m_transform[1] * m_transform[1]);
+    return sqrt(xScaleSquared());
+}
+
+double AffineTransform::yScaleSquared() const
+{
+    return m_transform[2] * m_transform[2] + m_transform[3] * m_transform[3];
 }
 
 double AffineTransform::yScale() const
 {
-    return sqrt(m_transform[2] * m_transform[2] + m_transform[3] * m_transform[3]);
+    return sqrt(yScaleSquared());
 }
 
 double AffineTransform::det() const