Add confirmation dialog when enabling a 3rd party IME.

chrome/app/chromeos_strings.grdp

Index: chrome/app/chromeos_strings.grdp
diff --git a/chrome/app/chromeos_strings.grdp b/chrome/app/chromeos_strings.grdp
index 983ce0ee15966b80eaa6ba030c68b71b63c8b23e..9d670ff04bf8689e74f6c25d64788104cdfc42db 100644
--- a/chrome/app/chromeos_strings.grdp
+++ b/chrome/app/chromeos_strings.grdp
@@ -3234,6 +3234,20 @@ Press any key to continue exploring.
            desc="The label for languages with no Input Methods">
     This language doesn't have any input methods
   </message>
+  <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_THIRD_PARTY_WARNING_CONFIRM_BUTTON">
+    OK
+  </message>
+  <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_THIRD_PARTY_WARNING_CANCEL_BUTTON">
+    Cancel
+  </message>
+  <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_THIRD_PARTY_WARNING_TITLE"
+           desc="The title showing in the warning dialog when enabling a 3rd party Input Method">
+    Third party input method
+  </message>
+  <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_THIRD_PARTY_WARNING_MESSAGE"
+           desc="The description showing in the warning dialog when enabling a 3rd party Input Method">
+    This input method may be able to collect all the text you type, including personal data like passwords and credit card numbers. It comes from the extension "<ph name="EXTENSION_NAME">$1<ex>Google Input Tools extension</ex></ph>". Use this input method?
+  </message>
   <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_SIGN_OUT_BUTTON"
            desc="The label for the sign out button for changing UI language">
     Sign out