Oilpan: extend tracing over WebFrame trees.

Source/web/WebFrame.cpp

Index: Source/web/WebFrame.cpp
diff --git a/Source/web/WebFrame.cpp b/Source/web/WebFrame.cpp
index 826f69d06bb99574a13a752590594315a9d81917..82fc8c78ee8d4de009864ffb0c8b0eed9d4f150c 100644
--- a/Source/web/WebFrame.cpp
+++ b/Source/web/WebFrame.cpp
@@ -231,19 +231,52 @@ WebFrame::~WebFrame()
     m_openedFrameTracker.reset(0);
 }
 
-void WebFrame::traceChildren(Visitor* visitor, WebFrame* frame)
+void WebFrame::traceFrame(Visitor* visitor, WebFrame* frame)
 {
 #if ENABLE(OILPAN)
-    // Trace the children frames.
-    WebFrame* child = frame ? frame->firstChild() : 0;
-    while (child) {
-        if (child->isWebLocalFrame())
-            visitor->trace(toWebLocalFrameImpl(child));
-        else
-            visitor->trace(toWebRemoteFrameImpl(child));
-
-        child = child->nextSibling();
-    }
+    if (!frame)
+        return;
+
+    if (frame->isWebLocalFrame())
+        visitor->trace(toWebLocalFrameImpl(frame));
+    else
+        visitor->trace(toWebRemoteFrameImpl(frame));
+#endif
+}
+
+bool WebFrame::isAlive(Visitor* visitor, WebFrame* frame)
+{
+#if ENABLE(OILPAN)
+    if (!frame)
+        return true;

[haraken, 2014/09/24 14:13:04]

Shouldn't this be false?

[sof, 2014/09/24 14:24:34]

It could be, I'll move the null check to the call site instead and avoid the
repeated frame->m_opener clearing that way.

+
+    if (frame->isWebLocalFrame())
+        return visitor->isAlive(toWebLocalFrameImpl(frame));
+
+    return visitor->isAlive(toWebRemoteFrameImpl(frame));
+#else

[haraken, 2014/09/24 14:13:04]

Is it possible that isAlive is called in non-oilpan?

[sof, 2014/09/24 14:24:34]

Not possible, but I've resisted the temptation to use "#if ENABLE(OILPAN)"
inside "#if BLINK_IMPLEMENTATION" blocks in public/ header files. Is it allowed?

[haraken, 2014/09/24 14:28:51]

I'd guess it's allowed.

Even if it's not allowed, you can write ASSERT_NOT_REACHED here since non-oilpan
doesn't call the isAlive method.

+    return true;
+#endif
+}
+
+void WebFrame::traceFrames(Visitor* visitor, WebFrame* frame)
+{
+#if ENABLE(OILPAN)
+    ASSERT(frame);
+    traceFrame(visitor, frame->m_parent);
+    for (WebFrame* child = frame->firstChild(); child; child = child->nextSibling())
+        traceFrame(visitor, child);
+    // m_opener is a weak reference.
+    frame->m_openedFrameTracker->traceFrames(visitor);
+#endif
+}
+
+void WebFrame::clearWeakFrames(Visitor* visitor, WebFrame* frame)
+{
+#if ENABLE(OILPAN)
+    ASSERT(frame);
+    if (!isAlive(visitor, frame->m_opener))
+        frame->m_opener = nullptr;
 #endif
 }