Add isServiceReady API to ImsManager

 -- Add isServiceReady to check if ImsService is ready to
    send requests to lower layers or not.

Test: Manual
Bug: 63920021
Change-Id: I97e4af1e6eb428956d5f343a4628aba6857f37b8
diff --git a/src/java/com/android/ims/ImsManager.java b/src/java/com/android/ims/ImsManager.java
index a77abcd..a782baf 100644
--- a/src/java/com/android/ims/ImsManager.java
+++ b/src/java/com/android/ims/ImsManager.java
@@ -1361,6 +1361,14 @@
         return mImsServiceProxy.isBinderAlive();
     }
 
+    /*
+     * Returns a flag indicating whether the IMS service is ready to send requests to lower layers.
+     */
+    public boolean isServiceReady() {
+        connectIfServiceIsAvailable();
+        return mImsServiceProxy.isBinderReady();
+    }
+
     /**
      * If the service is available, try to reconnect.
      */