Expose Document::isPrivilegedContext from WebDocument

Source/core/dom/ExecutionContext.h

Index: Source/core/dom/ExecutionContext.h
diff --git a/Source/core/dom/ExecutionContext.h b/Source/core/dom/ExecutionContext.h
index 5fdbd76630c84eb689a9301cbb32662715ade20e..c5f8fc0826178f6cd5dc10c0915b2e545a326bb4 100644
--- a/Source/core/dom/ExecutionContext.h
+++ b/Source/core/dom/ExecutionContext.h
@@ -99,7 +99,7 @@ public:
 
     virtual void reportBlockedScriptExecutionToInspector(const String& directiveText) = 0;
 
-    virtual SecurityContext& securityContext() = 0;
+    virtual const SecurityContext& securityContext() const = 0;
     KURL contextURL() const { return virtualURL(); }
     KURL contextCompleteURL(const String& url) const { return virtualCompleteURL(url); }
 
@@ -152,7 +152,7 @@ public:
 
     // Decides whether this context is privileged, as described in
     // https://w3c.github.io/webappsec/specs/powerfulfeatures/#settings-privileged.
-    virtual bool isPrivilegedContext(String& errorMessage, const PrivilegeContextCheck = StandardPrivilegeCheck) = 0;
+    virtual bool isPrivilegedContext(String& errorMessage, const PrivilegeContextCheck = StandardPrivilegeCheck) const = 0;
 
     virtual void setReferrerPolicy(ReferrerPolicy);
     ReferrerPolicy referrerPolicy() const { return m_referrerPolicy; }