CSSStyleSheetResource should cache decoded text instead of raw bytes

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 4218572b31a22db8d713a0e464814c9481653d25..9ee2db13e7c794667b5ddb8c68ac656f7171d98c 100644
--- a/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
@@ -426,17 +426,35 @@ void LinkStyle::setCSSStyleSheet(
   // See the comment in PendingScript.cpp about why this check is necessary
   // here, instead of in the resource fetcher. https://crbug.com/500701.
   if (!cachedStyleSheet->errorOccurred() &&
-      m_owner->fastHasAttribute(HTMLNames::integrityAttr) &&
-      cachedStyleSheet->resourceBuffer() &&
-      !SubresourceIntegrity::CheckSubresourceIntegrity(
-          *m_owner, cachedStyleSheet->resourceBuffer()->data(),
-          cachedStyleSheet->resourceBuffer()->size(), KURL(baseURL, href),
-          *cachedStyleSheet)) {
-    m_loading = false;
-    removePendingSheet();
-    notifyLoadedSheetAndAllCriticalSubresources(
-        Node::ErrorOccurredLoadingSubresource);
-    return;
+      !m_owner->fastGetAttribute(HTMLNames::integrityAttr).isEmpty() &&
+      !cachedStyleSheet->integrityMetadata().isEmpty()) {
+    ResourceIntegrityDisposition disposition =
+        cachedStyleSheet->integrityDisposition();
+
+    if (disposition == ResourceIntegrityDisposition::NotChecked)

[Charlie Harrison, 2016/10/05 15:24:49]

nit: A conditional branch just for a DCHECK isn't great style. You can just
combine the conditions within the DCHECK:

DCHECK(disposition != ResourceIntegrityDisposition::NotChecked || 
       cachedStyleSheet->sheetText().isNull());

(too bad DCHECK_IMPLIES got removed from the codebase)

[kouhei (in TOK), 2016/10/06 12:02:36]

Done.

+      DCHECK(!cachedStyleSheet->sheetText().isNull());
+
+    if (disposition == ResourceIntegrityDisposition::NotChecked &&
+        cachedStyleSheet->resourceBuffer()) {
+      if (SubresourceIntegrity::CheckSubresourceIntegrity(
+              *m_owner, cachedStyleSheet->resourceBuffer()->data(),
+              cachedStyleSheet->resourceBuffer()->size(), KURL(baseURL, href),
+              *cachedStyleSheet))
+        disposition = ResourceIntegrityDisposition::Passed;
+      else
+        disposition = ResourceIntegrityDisposition::Failed;
+
+      const_cast<CSSStyleSheetResource*>(cachedStyleSheet)

[Charlie Harrison, 2016/10/05 15:24:48]

The const_cast is not ideal, but I can't think of a way around it without
significant refactors.

Ideas:
 - Change setCSSStyleSheet to return the disposition, and cache it in the
resource from the caller.
 - Call it out for removal when crbug.com/500701 is addressed with a comment.

+          ->setIntegrityDisposition(disposition);
+    }
+
+    if (disposition == ResourceIntegrityDisposition::Failed) {
+      m_loading = false;
+      removePendingSheet();
+      notifyLoadedSheetAndAllCriticalSubresources(
+          Node::ErrorOccurredLoadingSubresource);
+      return;
+    }
   }
 
   CSSParserContext parserContext(m_owner->document(), nullptr, baseURL,