[Autofill Assistant] Set default state to checked

Since we expect this feature has positive impact, so it would
better to not asking again and again.

Bug: 806868
Change-Id: I4dd50a60a9dc350cb0710d333f1489d3a4967a5d
Reviewed-on: https://chromium-review.googlesource.com/c/1351582Reviewed-by: Mathias Carlen <mcarlen@chromium.org>
Commit-Queue: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610986}

chrome/android/java/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantUiDelegate.java

@@ -776,6 +776,8 @@ class AutofillAssistantUiDelegate {
                                 .inflate(R.layout.init_screen, mCoordinatorView)
                                 .findViewById(R.id.init_screen);
 
+        // Set default state to checked.
+        ((CheckBox) initView.findViewById(R.id.checkbox_dont_show_init_again)).setChecked(true);
         initView.findViewById(R.id.button_init_ok)
                 .setOnClickListener(unusedView -> onInitClicked(true, initView));
         initView.findViewById(R.id.button_init_not_ok)