WebURLRequest: Track the requesting document's URL through navigations.

Source/platform/network/ResourceRequest.h

Index: Source/platform/network/ResourceRequest.h
diff --git a/Source/platform/network/ResourceRequest.h b/Source/platform/network/ResourceRequest.h
index 7a1dbf189cda95b8ea7e748d82dfbc60d5a2260f..eb8d9217f0513872eb7fe4ed5d9352fa63ecfc30 100644
--- a/Source/platform/network/ResourceRequest.h
+++ b/Source/platform/network/ResourceRequest.h
@@ -100,6 +100,9 @@ public:
     const KURL& firstPartyForCookies() const;
     void setFirstPartyForCookies(const KURL& firstPartyForCookies);
 
+    const KURL& requestorURL() const;
+    void setRequestorURL(const KURL&);
+
     const AtomicString& httpMethod() const;
     void setHTTPMethod(const AtomicString&);
 
@@ -240,6 +243,7 @@ private:
     ResourceRequestCachePolicy m_cachePolicy;
     double m_timeoutInterval; // 0 is a magic value for platform default on platforms that have one.
     KURL m_firstPartyForCookies;
+    KURL m_requestorURL;
     AtomicString m_httpMethod;
     HTTPHeaderMap m_httpHeaderFields;
     RefPtr<FormData> m_httpBody;
@@ -289,6 +293,7 @@ public:
     ResourceRequestCachePolicy m_cachePolicy;
     double m_timeoutInterval;
     KURL m_firstPartyForCookies;
+    KURL m_requestorURL;
 
     String m_httpMethod;
     OwnPtr<CrossThreadHTTPHeaderMapData> m_httpHeaders;