Oilpan: extend tracing over WebFrame trees.

Source/web/OpenedFrameTracker.cpp

Index: Source/web/OpenedFrameTracker.cpp
diff --git a/Source/web/OpenedFrameTracker.cpp b/Source/web/OpenedFrameTracker.cpp
index 2120f339a6d4f91c0ebb075c83f58f4eae36aed4..ec3f62f253cb84037081a08a0310e3db60f94761 100644
--- a/Source/web/OpenedFrameTracker.cpp
+++ b/Source/web/OpenedFrameTracker.cpp
@@ -5,6 +5,7 @@
 #include "config.h"
 #include "web/OpenedFrameTracker.h"
 
+#include "platform/heap/Handle.h"
 #include "public/web/WebFrame.h"
 
 namespace blink {
@@ -15,7 +16,10 @@ OpenedFrameTracker::OpenedFrameTracker()
 
 OpenedFrameTracker::~OpenedFrameTracker()
 {
+#if !ENABLE(OILPAN)
+    // Oilpan takes care of clearing weak m_opener fields during GC.
     updateOpener(0);
+#endif
 }
 
 bool OpenedFrameTracker::isEmpty() const
@@ -40,4 +44,13 @@ void OpenedFrameTracker::updateOpener(WebFrame* frame)
         (*it)->m_opener = frame;
 }
 
+void OpenedFrameTracker::traceFrames(Visitor* visitor)
+{
+#if ENABLE(OILPAN)
+    HashSet<WebFrame*>::iterator end = m_openedFrames.end();
+    for (HashSet<WebFrame*>::iterator it = m_openedFrames.begin(); it != end; ++it)
+        WebFrame::traceFrame(visitor, *it);
+#endif
+}
+
 } // namespace blink