Exclude border from overflow scroller in sticky constraints.

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

Index: third_party/WebKit/Source/core/layout/LayoutBoxModelObjectTest.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBoxModelObjectTest.cpp b/third_party/WebKit/Source/core/layout/LayoutBoxModelObjectTest.cpp
index 8a08b8668ce0334c1c86460446a2fc880892e0a9..1f4b15ccab09468c8eb6a5408909e0b69b9494a2 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBoxModelObjectTest.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBoxModelObjectTest.cpp
@@ -34,8 +34,8 @@ TEST_F(LayoutBoxModelObjectTest, StickyPositionConstraints) {
       "}"
       "#container { box-sizing: border-box; position: relative; top: 100px; "
       "height: 400px; width: 200px; padding: 10px; border: 5px solid black; }"
-      "#scroller { height: 100px; overflow: auto; position: relative; top: "
-      "200px; }"
+      "#scroller { width: 400px; height: 100px; overflow: auto; "
+      "position: relative; top: 200px; border: 2px solid black; }"
       ".spacer { height: 1000px; }</style>"
       "<div id='scroller'><div id='container'><div "
       "id='sticky'></div></div><div class='spacer'></div></div>");
@@ -62,6 +62,10 @@ TEST_F(LayoutBoxModelObjectTest, StickyPositionConstraints) {
   ASSERT_EQ(
       IntRect(15, 115, 100, 100),
       enclosingIntRect(getScrollContainerRelativeStickyBoxRect(constraints)));
+
+  // The sticky constraining rect also doesn't include the border offset.

[chrishtr, 2016/11/12 00:17:20]

Please add a vertical-rl example also.

[flackr, 2016/11/14 14:50:14]

Done.

+  ASSERT_EQ(IntRect(0, 50, 400, 100),
+            enclosingIntRect(sticky->computeStickyConstrainingRect()));
 }
 
 // Verifies that the sticky constraints are not affected by transforms
@@ -144,7 +148,7 @@ TEST_F(LayoutBoxModelObjectTest, StickyPositionContainerIsScroller) {
       "<style>#sticky { position: sticky; top: 0; width: 100px; height: 100px; "
       "}"
       "#scroller { height: 100px; width: 400px; overflow: auto; position: "
-      "relative; top: 200px; }"
+      "relative; top: 200px; border: 2px solid black; }"
       ".spacer { height: 1000px; }</style>"
       "<div id='scroller'><div id='sticky'></div><div "
       "class='spacer'></div></div>");