Introduce firstRangeOf() as replacement of VisibleSelection::firstRange()

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index ec12fcb9ef8e0eadf3bdde9ba53be5d6895ec921..c1d869d5578d8902a442cab24cdaafa24c1b1728 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -2370,7 +2370,7 @@ WebTextInputInfo WebViewImpl::textInputInfo()
     if (info.value.isEmpty())
         return info;
 
-    if (RefPtrWillBeRawPtr<Range> range = selection.selection().firstRange()) {
+    if (RefPtrWillBeRawPtr<Range> range = firstRangeOf(selection.selection())) {
         PlainTextRange plainTextRange(PlainTextRange::create(*element, *range.get()));
         if (plainTextRange.isNotNull()) {
             info.selectionStart = plainTextRange.start();