Paint invalidation tests of composited-non-stacking-context descendant

LayoutTests/paint/invalidation/fixed-position-descendant-paint-offset-indirect.html

Index: LayoutTests/paint/invalidation/fixed-position-descendant-paint-offset-indirect.html
diff --git a/LayoutTests/paint/invalidation/fixed-position-descendant-paint-offset-indirect.html b/LayoutTests/paint/invalidation/fixed-position-descendant-paint-offset-indirect.html
index c31b53c0a78985b3632b2a3f50a1a894e0c8e1a2..5a81fea52a30631f0e64fee0c6efe03bfa53c645 100644
--- a/LayoutTests/paint/invalidation/fixed-position-descendant-paint-offset-indirect.html
+++ b/LayoutTests/paint/invalidation/fixed-position-descendant-paint-offset-indirect.html
@@ -10,10 +10,14 @@
     position: relative;
     width: 100px;
     height: 100px;
+    top: 50px;

[Xianzhu, 2015/08/25 18:35:59]

This is added to avoid it from overlapping with #composited-non-stacking-context
which would cause this div to be composited.

[chrishtr, 2015/08/25 18:49:03]

Please add a test instead of modifying this one. Otherwise we lose test
coverage.

[Xianzhu, 2015/08/25 18:52:40]

Actually this fixes coverage of the original test which was the same as
fixed-position-descendant-paint-offset.html because
#composited-non-stacking-context did nothing without the added properties.

     background-color: green;
 }
 
 #composited-non-stacking-context {
+    width: 20px;
+    height: 20px;
+    background-color: white;

[Xianzhu, 2015/08/25 18:35:59]

Note: these properties are added to ensure the div is composited. Otherwise it's
not because it's empty.

     backface-visibility: hidden;
 }
 </style>