Fix ClearBrowserDataBrowserTest.CommitButtonDisabledWhileDeletionInProgress flake.

chrome/browser/ui/webui/options/options_ui_browsertest.cc

Index: chrome/browser/ui/webui/options/options_ui_browsertest.cc
diff --git a/chrome/browser/ui/webui/options/options_ui_browsertest.cc b/chrome/browser/ui/webui/options/options_ui_browsertest.cc
index 0313cc4dc807768ea539470a91e448dd47a52524..5d8a70ad958d0a11769a3e23e671b4538eaf3a0b 100644
--- a/chrome/browser/ui/webui/options/options_ui_browsertest.cc
+++ b/chrome/browser/ui/webui/options/options_ui_browsertest.cc
@@ -130,6 +130,13 @@ void OptionsUIBrowserTest::NavigateToSettingsSubpage(
       subscription = options_ui->RegisterOnFinishedLoadingCallback(
           message_loop_runner->QuitClosure());
   message_loop_runner->Run();
+
+  // The OnFinishedLoading event, which indicates that all WebUI initialization
+  // methods have been called on the JS side, is temporally unrelated to whether
+  // or not the WebContents considers itself to have finished loading. We want
+  // to wait for this too, however, because, e.g. this is a sufficient condition
+  // to get the focus properly placed on a form element.
+  content::WaitForLoadStop(web_contents);
 }
 
 void OptionsUIBrowserTest::NavigateToSettingsFrame() {