Do not show translate bar for MHTML files.

url/gurl.h

Index: url/gurl.h
diff --git a/url/gurl.h b/url/gurl.h
index 6e582499836b4bcc900983cf7c76348aa9329515..b7dcf308fc3bfbcff7d0614661a0e786da7345ea 100644
--- a/url/gurl.h
+++ b/url/gurl.h
@@ -292,6 +292,11 @@ class URL_EXPORT GURL {
   // is everything after the last slash in the path. This may be empty.
   std::string ExtractFileName() const;
 
+  // Extracts the file extension portion of the path and returns it. The file
+  // extension is everything after the last dot in the file name. This may be
+  // empty.
+  std::string ExtractFileExtension() const;
+
   // Returns the path that should be sent to the server. This is the path,
   // parameter, and query portions of the URL. It is guaranteed to be ASCII.
   std::string PathForRequest() const;