Avoid having uninitialized values for DateTimeChooserParameters fields.

When the date/time doesn't have "date-time-edit" in its shadow subtree,
the is_ampm_first, has_ampm, has_second, has_millisecond fields are going
to be uninitialized.

This CL ensures that the fields are always initialized.

Bug: 1026906
Change-Id: Ibfa8dd9993cf291402407e3592de82387c3d68b3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1927574Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Ionel Popescu <iopopesc@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#717703}

third_party/blink/renderer/core/html/forms/multiple_fields_temporal_input_type_view.cc

@@ -324,6 +324,11 @@ bool MultipleFieldsTemporalInputTypeView::SetupDateTimeChooserParameters(
     parameters.has_ampm = edit->HasField(DateTimeField::kAMPM);
     parameters.has_second = edit->HasField(DateTimeField::kSecond);
     parameters.has_millisecond = edit->HasField(DateTimeField::kMillisecond);
+  } else {
+    parameters.is_ampm_first = false;
+    parameters.has_ampm = false;
+    parameters.has_second = false;
+    parameters.has_millisecond = false;
   }
 
   return GetElement().SetupDateTimeChooserParameters(parameters);