Embedding-CSP: Adding `const` to method signatures.

third_party/WebKit/Source/core/frame/csp/CSPDirectiveList.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/frame/csp/CSPDirectiveList.h"
 
 #include "bindings/core/v8/SourceLocation.h"
 #include "core/dom/Document.h"
 #include "core/dom/SecurityContext.h"
 #include "core/dom/SpaceSplitString.h"
@@ skipping 1150 matching lines @@
     treatAsPublicAddress(name, value);
   } else if (type == ContentSecurityPolicy::DirectiveType::RequireSRIFor &&
              m_policy->experimentalFeaturesEnabled()) {
     parseRequireSRIFor(name, value);
   } else {
     m_policy->reportUnsupportedDirective(name);
   }
 }
 
 SourceListDirective* CSPDirectiveList::operativeDirective(
-    const ContentSecurityPolicy::DirectiveType& type) {
+    const ContentSecurityPolicy::DirectiveType& type) const {
   switch (type) {
     // Directives that do not have a default directive.
     case ContentSecurityPolicy::DirectiveType::BaseURI:
       return m_baseURI.get();
     case ContentSecurityPolicy::DirectiveType::DefaultSrc:
       return m_defaultSrc.get();
     case ContentSecurityPolicy::DirectiveType::FrameAncestors:
       return m_frameAncestors.get();
     case ContentSecurityPolicy::DirectiveType::FormAction:
       return m_formAction.get();
@@ skipping 99 matching lines @@
   visitor->trace(m_imgSrc);
   visitor->trace(m_mediaSrc);
   visitor->trace(m_manifestSrc);
   visitor->trace(m_objectSrc);
   visitor->trace(m_scriptSrc);
   visitor->trace(m_styleSrc);
   visitor->trace(m_workerSrc);
 }
 
 }  // namespace blink