Fix current/new password assignment in iOS PasswordController

ios/chrome/browser/passwords/password_controller.mm

Index: ios/chrome/browser/passwords/password_controller.mm
diff --git a/ios/chrome/browser/passwords/password_controller.mm b/ios/chrome/browser/passwords/password_controller.mm
index fc5d885b3bc2553709c48354ab7457b59e3033a7..b7478f81e2c266169cc5517d72902fd1e63fcbb2 100644
--- a/ios/chrome/browser/passwords/password_controller.mm
+++ b/ios/chrome/browser/passwords/password_controller.mm
@@ -691,37 +691,40 @@ bool GetPageURLAndCheckTrustLevel(web::WebState* web_state, GURL* page_url) {
       form->password_value = values[0];
       break;
     case 2: {
-      if (values[0] == values[1]) {
-        // Treat two identical passwords as a single password.
-        form->password_element = elements[0];
-        form->password_value = values[0];
-      } else {
-        // Assume first is old password, second is new (no choice but to guess).
+      if (values[0].length() && values[0] == values[1]) {

[vabr (Chromium), 2016/07/06 11:41:12]

nit: Please use !empty() instead of length(). It makes the code slightly easier
to read, and also allows optimisations on the side of the library (detecting
emptiness is an easier task than computing the length precisely).

Also below.

[Jackie Quinn, 2016/07/06 11:51:15]

Done.

+        // Treat two identical passwords as a single password new password, with
+        // confirmation. This can be either be a sign-up form or a password
+        // change form that does not ask for a new password.
         form->new_password_element = elements[0];
         form->new_password_value = values[0];
-        form->password_element = elements[1];
-        form->password_value = values[1];
+      } else {
+        // Assume first is old password, second is new (no choice but to guess).
+        form->password_element = elements[0];
+        form->password_value = values[0];
+        form->new_password_element = elements[1];
+        form->new_password_value = values[1];
       }
       break;
       default:
-        if (values[0] == values[1] && values[0] == values[2]) {
-          // All three passwords the same? Just treat as one and hope.
+        if (values[0].length() && values[0] == values[1] &&
+            values[0] == values[2]) {
+          // All three passwords the same? This does not make sense, do not
+          // add the password element.
+          break;
+        } else if (values[0] == values[1]) {
+          // First two the same and the third different implies that the old
+          // password is the duplicated one.
           form->password_element = elements[0];
           form->password_value = values[0];
-        } else if (values[0] == values[1]) {
-          // Two the same and one different -> old password is the duplicated
-          // one.
-          form->new_password_element = elements[0];
-          form->new_password_value = values[0];
-          form->password_element = elements[2];
-          form->password_value = values[2];
+          form->new_password_element = elements[2];
+          form->new_password_value = values[2];
         } else if (values[1] == values[2]) {
           // Two the same and one different -> new password is the duplicated
           // one.
-          form->new_password_element = elements[0];
-          form->new_password_value = values[0];
-          form->password_element = elements[1];
-          form->password_value = values[1];
+          form->password_element = elements[0];
+          form->password_value = values[0];
+          form->new_password_element = elements[1];
+          form->new_password_value = values[1];
         } else {
           // Three different passwords, or first and last match with middle
           // different. No idea which is which, so no luck.