iframe updates its parent scrollable area set when its visibility change

LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change-expected.txt

Index: LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change-expected.txt
diff --git a/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change-expected.txt b/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change-expected.txt
index f3c809a9007f204f7d94e4eff94ffe3fe32489b0..f4e82954091f87b5591683aa2a53af87ddf0a93c 100644
--- a/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change-expected.txt
+++ b/LayoutTests/scrollingcoordinator/non-fast-scrollable-visibility-change-expected.txt
@@ -1,18 +1,33 @@
-This should be covered by the ONLY visible green overlay.
-This test ensures that changing visibility of a non-fast scrollable area correctly updates list of non-fast scrollable areas. (See http://crbug.com/434982)
+
+Two 250px by 250px squares should be visible and fully covered by green overlays.
+
+This test ensures that changing visibility of a non-fast scrollable area correctly updates list of non-fast scrollable areas (See http://crbug.com/434982). Two types of non-fast scrollable regions are covered: div, and iframe.
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
+running tests for non-fast scrollable div
+PASS document.getElementById("div").style.display is "block"
+PASS nonFastScrollableRects.length is 1
+PASS rectToString(nonFastScrollableRects[0]) is "[0, 350, 250, 250]"
+PASS window.internals.needsLayoutCount() is 0
+PASS nonFastScrollableRects.length is 2
+PASS rectToString(nonFastScrollableRects[0]) is "[0, 50, 250, 250]"
+PASS rectToString(nonFastScrollableRects[1]) is "[0, 350, 250, 250]"
+PASS window.internals.needsLayoutCount() is 0
+PASS nonFastScrollableRects.length is 1
+PASS rectToString(nonFastScrollableRects[0]) is "[0, 50, 250, 250]"
+running tests for non-fast scrollable iframe
+PASS document.getElementById("iframe").style.display is "block"
 PASS nonFastScrollableRects.length is 1
-PASS rectToString(nonFastScrollableRects[0]) is "[0, 300, 250, 250]"
+PASS rectToString(nonFastScrollableRects[0]) is "[0, 350, 250, 250]"
 PASS window.internals.needsLayoutCount() is 0
 PASS nonFastScrollableRects.length is 2
-PASS rectToString(nonFastScrollableRects[0]) is "[0, 0, 250, 250]"
-PASS rectToString(nonFastScrollableRects[1]) is "[0, 300, 250, 250]"
+PASS rectToString(nonFastScrollableRects[0]) is "[0, 50, 250, 250]"
+PASS rectToString(nonFastScrollableRects[1]) is "[0, 350, 250, 250]"
 PASS window.internals.needsLayoutCount() is 0
 PASS nonFastScrollableRects.length is 1
-PASS rectToString(nonFastScrollableRects[0]) is "[0, 0, 250, 250]"
+PASS rectToString(nonFastScrollableRects[0]) is "[0, 50, 250, 250]"
 PASS successfullyParsed is true
 
 TEST COMPLETE