Set the target type when creating the request for main resource

public/platform/WebURLRequest.h

Index: public/platform/WebURLRequest.h
diff --git a/public/platform/WebURLRequest.h b/public/platform/WebURLRequest.h
index 7d9e4dcda03fa69796189c4431bfee4229f30c29..adbfb31fb83c81d377c95ae38ca0abb0ebe629e5 100644
--- a/public/platform/WebURLRequest.h
+++ b/public/platform/WebURLRequest.h
@@ -103,11 +103,7 @@ public:
         return *this;
     }
 
-    explicit WebURLRequest(const WebURL& url) : m_private(0)
-    {
-        initialize();
-        setURL(url);
-    }
+    explicit WebURLRequest(const WebURL&, bool isMainResource = false, bool isMainFrame = true);
 
     BLINK_PLATFORM_EXPORT void initialize();
     BLINK_PLATFORM_EXPORT void reset();