Display the cancel button on the input screen

It is highly recommended to display the cancel button in addition to the
OK button on the input screen according to GSMA PDATA.12 - SIM Toolkit
Device Requirements to improve Mobile Connect Customer Experience. The
result code shall be 0x10 - Proactive UICC session terminated by the
user.

Bug: 67083833
Test: Confirmed that the cancel button is added and works as expected.

Change-Id: Ifd73a970a9be19b1c064887be39fe813fa0ca1a5
diff --git a/src/com/android/stk/StkInputActivity.java b/src/com/android/stk/StkInputActivity.java
index a4e6daf..5c6087b 100644
--- a/src/com/android/stk/StkInputActivity.java
+++ b/src/com/android/stk/StkInputActivity.java
@@ -121,6 +121,12 @@
             mAcceptUsersInput = false;
             input = mTextIn.getText().toString();
             break;
+        case R.id.button_cancel:
+            mAcceptUsersInput = false;
+            cancelTimeOut();
+            appService.getStkContext(mSlotId).setPendingActivityInstance(this);
+            sendResponse(StkAppService.RES_ID_END_SESSION);
+            return;
         // Yes/No layout buttons.
         case R.id.button_yes:
             mAcceptUsersInput = false;
@@ -196,10 +202,12 @@
         mInstance = this;
         // Set buttons listeners.
         Button okButton = (Button) findViewById(R.id.button_ok);
+        Button cancelButton = (Button) findViewById(R.id.button_cancel);
         Button yesButton = (Button) findViewById(R.id.button_yes);
         Button noButton = (Button) findViewById(R.id.button_no);
 
         okButton.setOnClickListener(this);
+        cancelButton.setOnClickListener(this);
         yesButton.setOnClickListener(this);
         noButton.setOnClickListener(this);