a11Y for select all button

Add content description for select all button.

Screenshot: http://screen/kmYYExHOuTp
Bug: 63917180
Test: Manual, refer to screenshot
PiperOrigin-RevId: 164672361
Change-Id: If34f754f68824664270d7a76b1cb17da2f8ef01c
diff --git a/java/com/android/dialer/app/res/layout/call_log_fragment.xml b/java/com/android/dialer/app/res/layout/call_log_fragment.xml
index 8bbec95..efc08fb 100644
--- a/java/com/android/dialer/app/res/layout/call_log_fragment.xml
+++ b/java/com/android/dialer/app/res/layout/call_log_fragment.xml
@@ -36,6 +36,7 @@
         android:paddingLeft="@dimen/select_all_icon_padding"
         android:paddingRight="@dimen/select_all_icon_padding"
         android:gravity="center_vertical"
+        android:contentDescription="@string/select_all"
         android:src="@drawable/ic_empty_check_mark_white_24dp"/>
     <TextView
         android:id="@+id/select_all_view_text"