Add "previewing on hover" support for password field.

components/autofill/content/common/autofill_messages.h

Index: components/autofill/content/common/autofill_messages.h
diff --git a/components/autofill/content/common/autofill_messages.h b/components/autofill/content/common/autofill_messages.h
index 0fa84302fedee7c1cc7d7e4f5b3aeca4af514d47..cb9fc6a1252f615b3c57377c77dbfdbc73807f28 100644
--- a/components/autofill/content/common/autofill_messages.h
+++ b/components/autofill/content/common/autofill_messages.h
@@ -142,9 +142,15 @@ IPC_MESSAGE_ROUTED1(AutofillMsg_AcceptDataListSuggestion,
 IPC_MESSAGE_ROUTED1(AutofillMsg_GeneratedPasswordAccepted,
                     base::string16 /* generated_password */)
 
-// Tells the renderer that the user accepted a password autofill suggestion,
-// and that renderer should set the username and password to the given values.
-IPC_MESSAGE_ROUTED2(AutofillMsg_AcceptPasswordAutofillSuggestion,
+// Tells the renderer to fill the username and password with with given
+// values.
+IPC_MESSAGE_ROUTED2(AutofillMsg_FillPasswordSuggestion,
+                    base::string16 /* username */,
+                    base::string16 /* password */)
+
+// Tells the renderer to preview the username and password with the given
+// values.
+IPC_MESSAGE_ROUTED2(AutofillMsg_PreviewPasswordSuggestion,
                     base::string16 /* username */,
                     base::string16 /* password */)