Remove some dead NPAPI code after r363119.

content/child/multipart_response_delegate.h

Index: content/child/multipart_response_delegate.h
diff --git a/content/child/multipart_response_delegate.h b/content/child/multipart_response_delegate.h
index b76afdb4c2e9c26137b467be541e0ff65505ed96..506f4b49de9b1ecb599ff60de7db7538874bf9fe 100644
--- a/content/child/multipart_response_delegate.h
+++ b/content/child/multipart_response_delegate.h
@@ -83,12 +83,6 @@ class CONTENT_EXPORT MultipartResponseDelegate {
     loader_ = NULL;
   }
 
-  // Returns the multi part boundary string from the Content-type header
-  // in the response.
-  // Returns true on success.
-  static bool ReadMultipartBoundary(const blink::WebURLResponse& response,
-                                    std::string* multipart_boundary);
-
   // Returns the lower and higher content ranges from an individual multipart
   // in a multipart response.
   // Returns true on success.