Make document.rootScroller into an origin trial

third_party/WebKit/Source/core/dom/Document.idl

Index: third_party/WebKit/Source/core/dom/Document.idl
diff --git a/third_party/WebKit/Source/core/dom/Document.idl b/third_party/WebKit/Source/core/dom/Document.idl
index 9c103953e6985fcfcae96daf0f31a17831b01a78..826a96d7844f94c13164150258b5b8de1973783e 100644
--- a/third_party/WebKit/Source/core/dom/Document.idl
+++ b/third_party/WebKit/Source/core/dom/Document.idl
@@ -78,7 +78,7 @@ interface Document : Node {
     [NewObject] TreeWalker createTreeWalker(Node root, optional unsigned long whatToShow = 0xFFFFFFFF, optional NodeFilter? filter = null);
 
     // NonDocumentRootScroller (https://github.com/bokand/NonDocumentRootScroller)
-    [RaisesException=Setter, RuntimeEnabled=SetRootScroller, Measure] attribute Element? rootScroller;
+    [RaisesException=Setter, OriginTrialEnabled=RootScroller, Measure] attribute Element? rootScroller;

[iclelland, 2017/01/12 15:58:13]

You'll also need to add a block in installConditionalFeaturesForModules to add
the property to Document when the trial is enabled (this is the annoying manual
bit that we need to eventually generate).

When it sees a document object, it needs to run the generated
installRootScroller method on the prototype. I haven't checked this code too
carefully, but it should probably look something like:

  if (wrapperTypeInfo == &V8Document::wrapperTypeInfo) {
    if (OriginTrials::rootScrollerEnabled(executionContext)) {
      V8DocumentPartial::installRootScroller(isolate, world,
                                          v8::Local<v8::Object>(),
                                          prototypeObject, interfaceObject);
    }
  }

[bokan, 2017/01/12 16:11:59]

Do you mean in installConditionalFeatures? My feature isn't in a module but in
core.

[iclelland, 2017/01/12 19:26:41]

Yes, I totally mean that :) Sorry -- that's what I meant about not having
checked too closely.

s/V8DocumentPartial/V8Document/ then, as well.

 
     // FIXME: xmlEncoding/xmlVersion/xmlStandalone have been removed from the spec.
     [MeasureAs=DocumentXMLEncoding] readonly attribute DOMString? xmlEncoding;