Kill [SetWrapperReferenceFromReference] IDL extended attribute

Source/bindings/scripts/code_generator_v8.pm

Index: Source/bindings/scripts/code_generator_v8.pm
diff --git a/Source/bindings/scripts/code_generator_v8.pm b/Source/bindings/scripts/code_generator_v8.pm
index a554f2f090e7a318991dc654c0693d359a64a558..1167a3fbd8f37d54e92af5cc9a26ed312003b389 100644
--- a/Source/bindings/scripts/code_generator_v8.pm
+++ b/Source/bindings/scripts/code_generator_v8.pm
@@ -513,7 +513,7 @@ sub HeaderFilesForInterface
 sub NeedsVisitDOMWrapper
 {
     my $interface = shift;
-    return ExtendedAttributeContains($interface->extendedAttributes->{"Custom"}, "VisitDOMWrapper") || $interface->extendedAttributes->{"SetWrapperReferenceFrom"} || $interface->extendedAttributes->{"SetWrapperReferenceFromReference"} || $interface->extendedAttributes->{"SetWrapperReferenceTo"} || SVGTypeNeedsToHoldContextElement($interface->name);
+    return ExtendedAttributeContains($interface->extendedAttributes->{"Custom"}, "VisitDOMWrapper") || $interface->extendedAttributes->{"SetWrapperReferenceFrom"} || $interface->extendedAttributes->{"SetWrapperReferenceTo"} || SVGTypeNeedsToHoldContextElement($interface->name);
 }
 
 sub GenerateVisitDOMWrapper
@@ -562,37 +562,26 @@ END
 END
     }
 
-    my $isReachableMethod = $interface->extendedAttributes->{"SetWrapperReferenceFrom"};
-    my $isReachableReferenceMethod = $interface->extendedAttributes->{"SetWrapperReferenceFromReference"};
-
-    if ($isReachableMethod || $isReachableReferenceMethod) {
+    my $setWrapperReferenceMethod = $interface->extendedAttributes->{"SetWrapperReferenceFrom"};
+    if ($setWrapperReferenceMethod) {
         AddToImplIncludes("bindings/v8/V8GCController.h");
         AddToImplIncludes("core/dom/Element.h");
-        if ($isReachableMethod) {
-            $code .= <<END;
-    if (Node* owner = impl->${isReachableMethod}()) {
-        Node* root = V8GCController::opaqueRootForGC(owner, isolate);
+        $code .= <<END;
+    // The ${setWrapperReferenceMethod}() method may return a reference or a pointer but
+    // RefPtr can be constructed from either.
+    if (RefPtr<Node> owner = PassRefPtr<Node>(impl->${setWrapperReferenceMethod}())) {

[adamk, 2014/02/26 17:55:38]

Why make a RefPTr here when we didn't make one before? Is this just to take
advantage of the reference constructor for PassRefPtr? If so, I wonder if you
could instead augment WTF::getPtr
(https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...)
to handle references...

[Inactive, 2014/02/26 18:01:56]

Yes, this is the trick, we construct a RefPtr because it can be constructed from
either a pointer or a reference and the implementation may return either (we
don't know).

Augmenting the WTF::getPtr() to take a reference in is a much better idea
though. I'll do this instead, thanks :)

+        Node* root = V8GCController::opaqueRootForGC(owner.get(), isolate);
         isolate->SetReferenceFromGroup(v8::UniqueId(reinterpret_cast<intptr_t>(root)), wrapper);
         return;
     }
 END
-        } else {
-            $code .= <<END;
-    Node* root = V8GCController::opaqueRootForGC(&impl->${isReachableReferenceMethod}(), isolate);
-    isolate->SetReferenceFromGroup(v8::UniqueId(reinterpret_cast<intptr_t>(root)), wrapper);
-}
-
-END
-        }
     }
 
-    if (!$isReachableReferenceMethod) {
-        $code .= <<END;
+    $code .= <<END;
     setObjectGroup(object, wrapper, isolate);
 }
 
 END
-    }
 
     $implementation{nameSpaceWebCore}->add($code);
 }