Add loadedNonEmptyDocument flag in FrameLoader for Resource Timing

Source/core/html/HTMLFrameOwnerElement.h

Index: Source/core/html/HTMLFrameOwnerElement.h
diff --git a/Source/core/html/HTMLFrameOwnerElement.h b/Source/core/html/HTMLFrameOwnerElement.h
index 35ead777e361bdda0b73e204a013322b158173cc..3aa92612de2b69881af5906f64ef4ee8e4b2354e 100644
--- a/Source/core/html/HTMLFrameOwnerElement.h
+++ b/Source/core/html/HTMLFrameOwnerElement.h
@@ -60,6 +60,9 @@ public:
 
     SandboxFlags sandboxFlags() const { return m_sandboxFlags; }
 
+    virtual bool loadedNonEmptyDocument() const { return false; }
+    virtual void didLoadNonEmptyDocument() {}

[Nate Chapin, 2013/04/30 19:55:58]

Hmm...I'm not sure whether it makes more sense to have this be virtual or just
have the boolean live down here on HTMLFrameOwnerElement.

[Pan, 2013/05/07 08:45:52]

HTMLFrameOwnerElement has derived and derived derived class other
HTMLIframeElement, so I suggest keep the interface here, and make the Boolean
live in HTMLIframeElement only， to less affect other element.

+
 protected:
     HTMLFrameOwnerElement(const QualifiedName& tagName, Document*);
     void setSandboxFlags(SandboxFlags);