Let ContentSecurityPolicy shared between imports and the master.

Source/core/frame/ContentSecurityPolicy.h

Index: Source/core/frame/ContentSecurityPolicy.h
diff --git a/Source/core/frame/ContentSecurityPolicy.h b/Source/core/frame/ContentSecurityPolicy.h
index ab122c27dc8f3948d86e52d1ed90bb8c373577c4..6fc26530165d13c045bcbc07c976d3e5fdefc260 100644
--- a/Source/core/frame/ContentSecurityPolicy.h
+++ b/Source/core/frame/ContentSecurityPolicy.h
@@ -32,6 +32,8 @@
 #include "platform/weborigin/ReferrerPolicy.h"
 #include "wtf/HashSet.h"
 #include "wtf/PassOwnPtr.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefCounted.h"
 #include "wtf/Vector.h"
 #include "wtf/text/StringHash.h"
 #include "wtf/text/TextPosition.h"
@@ -54,12 +56,12 @@ class SecurityOrigin;
 typedef int SandboxFlags;
 typedef Vector<OwnPtr<CSPDirectiveList> > CSPDirectiveListVector;
 
-class ContentSecurityPolicy {
+class ContentSecurityPolicy : public RefCounted<ContentSecurityPolicy> {
     WTF_MAKE_FAST_ALLOCATED;
 public:
-    static PassOwnPtr<ContentSecurityPolicy> create(ExecutionContextClient* client)
+    static PassRefPtr<ContentSecurityPolicy> create(ExecutionContextClient* client)
     {
-        return adoptPtr(new ContentSecurityPolicy(client));
+        return adoptRef(new ContentSecurityPolicy(client));
     }
     ~ContentSecurityPolicy();