Filter out data urls in the preload scanner

third_party/WebKit/Source/core/html/parser/PreloadRequest.h

Index: third_party/WebKit/Source/core/html/parser/PreloadRequest.h
diff --git a/third_party/WebKit/Source/core/html/parser/PreloadRequest.h b/third_party/WebKit/Source/core/html/parser/PreloadRequest.h
index 3b5722e5c01b10eb24cfb89c77f39959128f56a8..2c4ceeb42b157b064dfd182ac1ee1359ecd5fea2 100644
--- a/third_party/WebKit/Source/core/html/parser/PreloadRequest.h
+++ b/third_party/WebKit/Source/core/html/parser/PreloadRequest.h
@@ -30,6 +30,8 @@ class PreloadRequest {
     RequestTypeLinkRelPreload
   };
 
+  // TODO(csharrison): Move the implementation to the cpp file when html
+  // gets its own testing source set in html/BUILD.gn.
   static std::unique_ptr<PreloadRequest> create(

[Yoav Weiss, 2016/10/24 15:00:32]

Usually `create()` doesn't fail in normal circumstances. Could you rename to
createIfNeeded() or something similar?

[Charlie Harrison, 2016/10/24 17:39:48]

Done.

       const String& initiatorName,
       const TextPosition& initiatorPosition,
@@ -42,6 +44,11 @@ class PreloadRequest {
       const ClientHintsPreferences& clientHintsPreferences =
           ClientHintsPreferences(),
       RequestType requestType = RequestTypePreload) {
+    // Never preload data or ref urls.
+    if (resourceURL.isEmpty() || resourceURL.startsWith("#") ||

[Yoav Weiss, 2016/10/24 14:43:54]

Are absolute ref URLs an issue? What would happen with them?

[Charlie Harrison, 2016/10/24 14:49:31]

I think absolute ref URLs are okay because we really just don't want the URL to
canonicalize into a data URL. This will happen with relative ref URLs but not
absolute ref URLs. I can probably amend this comment to make that a little
clearer.

[Yoav Weiss, 2016/10/24 15:00:32]

Thanks. Clarifying that in the comment would be indeed helpful.

[Charlie Harrison, 2016/10/24 17:39:48]

Done.

+        protocolIs(resourceURL, "data")) {
+      return nullptr;
+    }
     return wrapUnique(new PreloadRequest(
         initiatorName, initiatorPosition, resourceURL, baseURL, resourceType,
         resourceWidth, clientHintsPreferences, requestType, referrerPolicy));