Implement cross-origin attributes using access check interceptors.

third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt

Index: third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt
diff --git a/third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt b/third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt
index 57f719302691eb175d1ea8f109d521eea691a73f..a673e169d2d06e7b1b154a6160d006dde4ad3c4b 100644
--- a/third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt
+++ b/third_party/WebKit/Source/bindings/IDLExtendedAttributes.txt
@@ -41,6 +41,7 @@ Constructor
 # FIXME: remove [ConstructorCallWith=Document], as can instead use
 # [ConstructorCallWith=ExecutionContext] + toDocument(executionContext)
 ConstructorCallWith=ExecutionContext|ScriptState|Document
+CrossOrigin=|Getter|Setter

[dcheng, 2016/11/02 07:45:32]

It turns out it can't be mutually exclusive.

I've changed this attribute so it works like this:

CrossOrigin with no arguments: defaults to just cross-origin getter.
CrossOrigin=Setter: only setter is cross-origin.
CrossOrigin=Getter: legal, but redundant with no argument version.
CrossOrigin=(Getter,Setter): both getter and setter are cross-origin (used for
window.location)

 Custom=|Getter|Setter|LegacyCallAsFunction|VisitDOMWrapper|PropertyGetter|PropertyEnumerator|PropertyQuery|CallPrologue|CallEpilogue
 CustomConstructor
 CustomElementCallbacks
@@ -48,7 +49,6 @@ Default=Undefined
 DependentLifetime
 DeprecateAs=*
 DoNotCheckConstants
-DoNotCheckSecurity=|Setter
 DoNotTestNewObject
 EnforceRange
 ExperimentalCallbackFunction