Fix flaky test HomepageSettingsFragmentTest#testChangeCustomized

Use criteria helper to wait desire state of UI to reduce flakiness.

Bug: 1056985
Change-Id: I8883722a62120cc4228e2fd5d7c3abc8b3ca071d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2080470
Commit-Queue: Theresa  <twellington@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Auto-Submit: Wenyu Fu <wenyufu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746145}

chrome/android/javatests/src/org/chromium/chrome/browser/settings/homepage/HomepageSettingsFragmentTest.java

@@ -41,6 +41,7 @@ import org.chromium.chrome.test.util.browser.Features;
 import org.chromium.components.browser_ui.widget.RadioButtonWithDescription;
 import org.chromium.components.browser_ui.widget.RadioButtonWithEditText;
 import org.chromium.components.embedder_support.util.UrlConstants;
+import org.chromium.content_public.browser.test.util.Criteria;
 import org.chromium.content_public.browser.test.util.CriteriaHelper;
 import org.chromium.content_public.browser.test.util.TestThreadUtils;
 import org.chromium.content_public.browser.test.util.TouchCommon;
@@ -542,9 +543,15 @@ public class HomepageSettingsFragmentTest {
         // Update the text box. To do this, request focus for customized radio button so that the
         // checked option will be changed.
         TestThreadUtils.runOnUiThreadBlocking(() -> {
-            mCustomUriRadioButton.requestFocus();
+            mCustomUriRadioButton.getEditTextForTests().requestFocus();
             mCustomUriRadioButton.setPrimaryText(TEST_URL_FOO);
         });
+        CriteriaHelper.pollUiThread(new Criteria("EditText never got the focus.") {
+            @Override
+            public boolean isSatisfied() {
+                return mCustomUriRadioButton.getEditTextForTests().isFocused();
+            }
+        });
 
         // Radio Button should switched to customized homepage.
         Assert.assertFalse(

components/browser_ui/widget/android/java/src/org/chromium/components/browser_ui/widget/RadioButtonWithEditText.java

@@ -13,6 +13,8 @@ import android.util.AttributeSet;
 import android.widget.EditText;
 import android.widget.TextView;
 
+import androidx.annotation.VisibleForTesting;
+
 import org.chromium.ui.KeyboardVisibilityDelegate;
 
 import java.util.ArrayList;
@@ -194,4 +196,12 @@ public class RadioButtonWithEditText extends RadioButtonWithDescription {
     public void setHint(int hintId) {
         mEditText.setHint(hintId);
     }
+
+    /**
+     * @return the EditText living inside this widget.
+     */
+    @VisibleForTesting
+    public EditText getEditTextForTests() {
+        return mEditText;
+    }
 }