Add an option in language settings for activating the IME menu.

chrome/app/chromeos_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- ChromeOS-specific strings (included from generated_resources.grd).
      Everything in this file is wrapped in <if expr="chromeos">. -->
 <grit-part>
   <message name="IDS_EMPTY_STRING" desc="Empty string, exist only to make code generic. No translation required.">
   </message>
   <!-- Idle logout dialog for retail mode -->
   <message name="IDS_IDLE_LOGOUT_TITLE" desc="Dialog title for the idle logout dialog. Used in retail mode only.">
     Are you still there?
   </message>
@@ skipping 3532 matching lines @@
     Configure...
   </message>
   <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_INPUT_METHOD"
            desc="The label for the section header for input methods">
     Input Method
   </message>
   <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_NO_INPUT_METHODS"
            desc="The label for languages with no Input Methods">
     This language doesn't have any input methods
   </message>
+  <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_ACTIVATE_IME_MENU"
+           desc="The label for activating IME menu on shelf.">
+    Show the input method menu on shelf.

[stevenjb, 2016/01/04 17:58:10]

s/on shelf/on the shelf/

[Azure Wei, 2016/01/05 06:48:03]

Done.

+  </message>
+  <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_ACTIVATE_IME_MENU_DESCRIPTION"
+           desc="The label for the description of showing input method menu.">
+    for easier switch of input methods, and access to more input features: voice input, handwriting and emoji.

[stevenjb, 2016/01/04 17:58:10]

s/for/For/
s/switch/switching/
s/, and/and/

[Azure Wei, 2016/01/05 06:48:03]

Done.

+  </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 &quot;<ph name="EXTENSION_NAME">$1<ex>Google Input Tools extension</ex></ph>&quot;. 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">
@@ skipping 2819 matching lines @@
     Installing
   </message>
   <message name="IDS_FLAGS_PRINTER_PROVIDER_SEARCH_APP_NAME" desc="Name of the flag used to enable launching Chrome Web Store Gallery widget app for searching for printer provider apps.">
     Chrome Web Store Gallery app for printer drivers
   </message>
   <message name="IDS_FLAGS_PRINTER_PROVIDER_SEARCH_APP_DESCRIPTION" desc="Description of a flag in chrome://flags that enables launching Chrome Web Store Gallery widget app for searching for printer provider apps.">
     Enables Chrome Web Store Gallery app for printer drivers. The app searches Chrome Web Store for extensions that support printing to a USB printer with specific USB ID.
   </message>
 
 </grit-part>