Adds the optional suggestedName to the chooseFile fileSystem API call.

chrome/common/extensions/api/file_system.idl

Index: chrome/common/extensions/api/file_system.idl
diff --git a/chrome/common/extensions/api/file_system.idl b/chrome/common/extensions/api/file_system.idl
index 7d9928eb7456edceb02499f1f9987ba1c4a8c938..f147956ed697095af985426daa972aa4606e0a22 100644
--- a/chrome/common/extensions/api/file_system.idl
+++ b/chrome/common/extensions/api/file_system.idl
@@ -18,6 +18,10 @@ namespace fileSystem {
     //
     // The default is 'openFile'.
     DOMString? type;
+
+    // The suggested file name that will be presented to the user as the
+    // default name to read or write. This is optional.
+    DOMString? suggestedName;
   };
   callback GetDisplayPathCallback = void (DOMString displayPath);
   callback FileEntryCallback = void ([instanceOf=fileEntry] object fileEntry);