Implemented HttpResponseHeadersFilter to set the CSP frame ancestors header to prevent iframe embedding

Change-Id: Ib58e452e291c4df407d30e8b914ab6aa20ae77bc
diff --git a/web/gui2/src/main/java/org/onosproject/ui/impl/gui2/HttpResponseHeadersFilter.java b/web/gui2/src/main/java/org/onosproject/ui/impl/gui2/HttpResponseHeadersFilter.java
new file mode 100644
index 0000000..68e4ac2
--- /dev/null
+++ b/web/gui2/src/main/java/org/onosproject/ui/impl/gui2/HttpResponseHeadersFilter.java
@@ -0,0 +1,29 @@
+package org.onosproject.ui.impl.gui2;
+ 
+import java.io.IOException;
+ 
+import javax.servlet.Filter;  
+import javax.servlet.FilterConfig;  
+import javax.servlet.FilterChain; 
+import javax.servlet.ServletException; 
+import javax.servlet.ServletRequest; 
+import javax.servlet.ServletResponse; 
+import javax.servlet.http.HttpServletResponse;
+ 
+ 
+public class HttpResponseHeadersFilter implements Filter {
+	
+    @Override
+    public void init(FilterConfig filterconfig){}
+
+    @Override
+	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
+	    HttpServletResponse resp = (HttpServletResponse) response;
+        resp.setHeader("Content-Security-Policy", "frame-ancestors 'none'");
+		chain.doFilter(request, resp);
+	}
+
+    @Override
+    public void destroy(){}
+
+}
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