Implement the "Delete Profile" button in the AutoFill editor.

Sync a null profile to BrowserSettings and remove the current
profile data from the editor UI and database.

Change-Id: I9ee911640882841b500914be5c381f686bc20e81
diff --git a/res/values/strings.xml b/res/values/strings.xml
index e5adc93..7d7fd0f 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -392,6 +392,8 @@
     <string name="autofill_profile_editor_save_profile">Save profile</string>
     <!-- Toast message displayed when the profile has been successfully saved [CHAR-LIMIT=none] -->
     <string name="autofill_profile_successful_save">Profile saved</string>
+    <!-- Toast message displayed when the profile has been successfully deleted [CHAR-LIMIT=none] -->
+    <string name="autofill_profile_successful_delete">Profile deleted</string>
     <!-- Button text to delete all the AutoFill profile data [CHAR-LIMIT=20] -->
     <string name="autofill_profile_editor_delete_profile">Delete profile data</string>