Add "previewing on hover" support for password field.

components/autofill/content/renderer/autofill_agent.h

Index: components/autofill/content/renderer/autofill_agent.h
diff --git a/components/autofill/content/renderer/autofill_agent.h b/components/autofill/content/renderer/autofill_agent.h
index 5c327db41c17fead30513b9d0cec867c22a8ffdb..fdd1bee2e4072c71a4cdc1390aa327709ecd116a 100644
--- a/components/autofill/content/renderer/autofill_agent.h
+++ b/components/autofill/content/renderer/autofill_agent.h
@@ -101,6 +101,7 @@ class AutofillAgent : public content::RenderViewObserver,
   void OnPreviewFieldWithValue(const base::string16& value);
   void OnAcceptDataListSuggestion(const base::string16& value);
   void OnAcceptPasswordAutofillSuggestion(const base::string16& username);
+  void OnPreviewPassword(const base::string16& username);
 
   // Called when interactive autocomplete finishes.
   void OnRequestAutocompleteResult(
@@ -212,6 +213,10 @@ class AutofillAgent : public content::RenderViewObserver,
   // messages to close the Autofill popup when it can't possibly be showing.
   bool is_popup_possibly_visible_;
 
+  // Whether the password is previewed. If true, the previewed username and
+  // password will be cleared on receiving ClearPreviewedForm message.
+  bool is_password_previewed_;

[Ilya Sherman, 2014/03/21 22:35:19]

Please move this state tracking and everything that depends on it into the
PasswordAutofillAgent class.

[ziran.sun, 2014/03/25 18:25:26]

Done.

+
   // Timestamp of first time forms are seen.
   base::TimeTicks forms_seen_timestamp_;