Introduce IsMemberOfExtension function into ExtensionIMEUtil.

chromeos/ime/extension_ime_util.h

Index: chromeos/ime/extension_ime_util.h
diff --git a/chromeos/ime/extension_ime_util.h b/chromeos/ime/extension_ime_util.h
index fd8505c971a55978e0d3b919301fe3f5fcbc5442..f439ec466836d49ec073fb264c08eb2285a6dc08 100644
--- a/chromeos/ime/extension_ime_util.h
+++ b/chromeos/ime/extension_ime_util.h
@@ -21,6 +21,11 @@ std::string CHROMEOS_EXPORT GetInputMethodID(const std::string& extension_id,
 // Returns true if the |input_method_id| is extension ime.
 bool CHROMEOS_EXPORT IsExtensionIME(const std::string& input_method_id);
 
+// Returns true if the |input_method| is member of |extension_id|, otherwise
+// return false.
+bool CHROMEOS_EXPORT IsMemberOfExtension(const std::string& input_method_id,
+                                         const std::string& extension_id);
+
 }  // extension_ime_util
 
 }  // namespace chromeos