Freeze global prototype chain per WebIDL

third_party/WebKit/LayoutTests/fast/dom/Window/window-custom-prototype-expected.txt

Index: third_party/WebKit/LayoutTests/fast/dom/Window/window-custom-prototype-expected.txt
diff --git a/third_party/WebKit/LayoutTests/fast/dom/Window/window-custom-prototype-expected.txt b/third_party/WebKit/LayoutTests/fast/dom/Window/window-custom-prototype-expected.txt
index 8065774dee767a829979558b208d186437702c7d..02aaf533bea5d79bb75aede062da7c0744c5d8cb 100644
--- a/third_party/WebKit/LayoutTests/fast/dom/Window/window-custom-prototype-expected.txt
+++ b/third_party/WebKit/LayoutTests/fast/dom/Window/window-custom-prototype-expected.txt
@@ -3,18 +3,19 @@ Test what happens when you set the window's prototype to various values.
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
-PASS __proto__ = window; __proto threw exception TypeError: Cyclic __proto__ value.
-PASS __proto__ = chainPointingBackToWindow; __proto__ threw exception TypeError: Cyclic __proto__ value.
+PASS __proto__ = window; __proto__ threw exception TypeError: Immutable prototype object '#<Window>' cannot have their prototype set.
+PASS __proto__ = chainPointingBackToWindow; __proto__ threw exception TypeError: Immutable prototype object '#<Window>' cannot have their prototype set.
 PASS __proto__ = 1; __proto__ is originalWindowPrototype
 PASS __proto__ = 'a string'; __proto__ is originalWindowPrototype
-PASS __proto__ = anotherObject; __proto__ is anotherObject
-PASS anotherObject.__proto__ = window; __proto__ threw exception TypeError: Cyclic __proto__ value.
-PASS __proto__ = 1; __proto__ is anotherObject
-PASS __proto__ = 'a string'; __proto__ is anotherObject
-PASS __proto__ = anotherObject; __proto__ is anotherObject
+PASS __proto__ = anotherObject; __proto__ threw exception TypeError: Immutable prototype object '#<Window>' cannot have their prototype set.
+PASS anotherObject.__proto__ = window; __proto__ is originalWindowPrototype
+PASS __proto__ = 1; __proto__ is originalWindowPrototype
+PASS __proto__ = 'a string'; __proto__ is originalWindowPrototype
+PASS __proto__ = anotherObject; __proto__ threw exception TypeError: Immutable prototype object '#<Window>' cannot have their prototype set.
 PASS __proto__ = originalWindowPrototype; __proto__ is originalWindowPrototype
 PASS anotherObject.__proto__ = window; anotherObject.__proto__ is window
-PASS __proto__ = null; window.__proto__ is undefined
+PASS __proto__ = null; __proto__ threw exception TypeError: Immutable prototype object '#<Window>' cannot have their prototype set.
+PASS location.__proto__.__proto__ = location threw exception TypeError: Cyclic __proto__ value.
 PASS successfullyParsed is true
 
 TEST COMPLETE