Add auto sign in slider in Clank settings.

chrome/android/java/strings/android_chrome_strings.grd

Index: chrome/android/java/strings/android_chrome_strings.grd
diff --git a/chrome/android/java/strings/android_chrome_strings.grd b/chrome/android/java/strings/android_chrome_strings.grd
index e340a64e76b9fb07e3fc426f3431d5bebf5e13be..af1ac5abaff74bd22ffb33016f05219b6baa561e 100644
--- a/chrome/android/java/strings/android_chrome_strings.grd
+++ b/chrome/android/java/strings/android_chrome_strings.grd
@@ -226,6 +226,12 @@
       </message>
 
       <!-- Save passwords preferences -->
+      <message name="IDS_PASSWORDS_AUTO_SIGNIN_TITLE" desc="Title for 'Auto sign-in' checkbox in the password dialog">

[newt (away), 2015/03/11 17:41:40]

"Title for checkbox to enable automatically signing the user in to websites."

[melandory, 2015/03/16 15:10:27]

Done.

+        Auto Sign-in
+      </message>
+      <message name="IDS_PASSWORDS_AUTO_SIGNIN_DESCRIPTION" desc="Text under 'Auto sign-in' checkbox">
+       Automatically sign in to websites using stored credential. When the feature is off, you'll be asked for verification every time before signing in to a website.

[newt (away), 2015/03/11 17:41:40]

s/credential/credentials ? Where did this string come from?

[melandory, 2015/03/16 15:10:27]

It's slightly modified string from mocks. Original string was saying: 
"Automatically sign in to apps and websites connected to your Account."

"Account" was removed because it restricts this feature only to sync users.
Desktop settings UI uses same string.

+      </message>
       <message name="IDS_PREFS_SAVED_PASSWORDS" desc="Title for the Saved Passwords preferences. [CHAR-LIMIT=32]">

[newt (away), 2015/03/11 17:41:40]

nit: move "Save passwords" string above the new strings

[melandory, 2015/03/16 15:10:27]

Done.

         Save passwords
       </message>