Implement the `require-sri-for` CSP directive

third_party/WebKit/Source/core/html/HTMLLinkElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp b/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
index 3976a5982562c857f8bef8ab7bfbf85fbf0d45c0..d6de4c946d35e2208ecc4f8ab3ae39c460b4f745 100644
--- a/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
@@ -753,6 +753,13 @@ void LinkStyle::process()
             request.setCrossOriginAccessControl(document().getSecurityOrigin(), crossOrigin);
             setFetchFollowingCORS();
         }
+
+        String integrityAttr = m_owner->fastGetAttribute(HTMLNames::integrityAttr);
+        if (!integrityAttr.isEmpty()) {
+            IntegrityMetadataSet metadataSet;
+            SubresourceIntegrity::parseIntegrityAttribute(integrityAttr, metadataSet);
+            request.setIntegrityMetadata(metadataSet);
+        }
         setResource(CSSStyleSheetResource::fetch(request, document().fetcher()));
 
         if (m_loading && !resource()) {