Add back pressed behavior for emergency dialer.

Bug: 17919944
Change-Id: Iacf2814b424e2b832f2df127b4a9ad4890e59e4a
diff --git a/src/com/android/phone/EmergencyDialer.java b/src/com/android/phone/EmergencyDialer.java
index e29d4c8..a8de874 100644
--- a/src/com/android/phone/EmergencyDialer.java
+++ b/src/com/android/phone/EmergencyDialer.java
@@ -38,6 +38,7 @@
 import android.text.method.DialerKeyListener;
 import android.util.Log;
 import android.view.KeyEvent;
+import android.view.MenuItem;
 import android.view.View;
 import android.view.WindowManager;
 import android.view.accessibility.AccessibilityManager;
@@ -606,6 +607,16 @@
         }
     }
 
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        final int itemId = item.getItemId();
+        if (itemId == android.R.id.home) {
+            onBackPressed();
+            return true;
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
     /**
      * Update the enabledness of the "Dial" and "Backspace" buttons if applicable.
      */