Don't create multiple WebRange objects for getting selection text.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index cfad1196e1904c640ff28fc875d8889788d4aee4..a098a695de76e036c4a2dbaee5165a1475ebc2d4 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -4057,8 +4057,7 @@ void RenderFrameImpl::SyncSelectionIfRequired() {
       length = location + length - offset + kExtraCharsBeforeAndAfterSelection;
       WebRange webrange = WebRange::fromDocumentRange(frame_, offset, length);
       if (!webrange.isNull())
-        text = WebRange::fromDocumentRange(
-            frame_, offset, length).toPlainText();
+        text = webrange.toPlainText();
     } else {
       offset = location;
       text = frame_->selectionAsText();