Transfer date/time value to the chooser as a double

public/web/WebDateTimeChooserParams.h

Index: public/web/WebDateTimeChooserParams.h
diff --git a/public/web/WebDateTimeChooserParams.h b/public/web/WebDateTimeChooserParams.h
index 918d636935a39270d8f33ca6e10190d89ef22b4b..2d2b3d9d2e7d097184de1cc86f53a94bfa55784a 100644
--- a/public/web/WebDateTimeChooserParams.h
+++ b/public/web/WebDateTimeChooserParams.h
@@ -41,7 +41,11 @@ struct WebDateTimeChooserParams {
     // Bounding rectangle of the requester element.
     WebRect anchorRectInScreen;
     // The current value of the requester element.
+    // FIXME: Remove. Deprecated in favor of doubleValue.
     WebString currentValue;
+    // The current value of the requester element as a double.
+    // NaN means empty value. Should not be infinity.
+    double doubleValue;
     // <datalist> option values associated to the requester element. These
     // values should not be shown to users. The vector size might be 0.
     WebVector<WebString> suggestionValues;