Add "previewing on hover" support for password field.

components/autofill/core/browser/password_autofill_manager.cc

Index: components/autofill/core/browser/password_autofill_manager.cc
diff --git a/components/autofill/core/browser/password_autofill_manager.cc b/components/autofill/core/browser/password_autofill_manager.cc
index 730c10e49d5d1b2282440dcf3dd406593cd3977b..d55a13a2bf969e585a51ac8a2dfa59b28e30355f 100644
--- a/components/autofill/core/browser/password_autofill_manager.cc
+++ b/components/autofill/core/browser/password_autofill_manager.cc
@@ -20,6 +20,21 @@ PasswordAutofillManager::PasswordAutofillManager(
 PasswordAutofillManager::~PasswordAutofillManager() {
 }
 
+bool PasswordAutofillManager::DidSelectAutofillSuggestion(
+    const FormFieldData& field,
+    const base::string16& username) {
+  PasswordFormFillData password;
+  if (!FindLoginInfo(field, &password))
+    return false;
+
+  if (WillFillUserNameAndPassword(username, password)) {
+    autofill_driver_->RendererShouldPreviewPassword(username);

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

Can we send both the username and the password down to the renderer?  The
eventual goal is to have the renderer not need to know *all* of the possible
passwords, and instead to only have that state available in the browser process.
 (In fact, if you'd like to work on more broadly implementing that task [as a
separate CL, of course], it would be quite helpful :)

It might be useful to first upload a CL implementing this for
DidAcceptAutofillSuggestion(), and then to implement something similar in this
CL.  Or you might prefer to start from this CL, and then improve the
implementation of DidAcceptAutofillSuggestion() in a later CL.

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

I might have a quick work on DidAcceptAutofillSuggestion() first and see if I
got what you meant. Then improve this one. I guess I need to file an issue on
this first?

[Ilya Sherman, 2014/03/25 19:45:27]

Sounds great -- thanks!  I've filed http://crbug.com/356310 to track this.

+    return true;
+  }
+
+  return false;
+ }
+
 bool PasswordAutofillManager::DidAcceptAutofillSuggestion(
     const FormFieldData& field,
     const base::string16& username) {