Reland: Fix setComposingText with empty text when newCursorPosition != 1

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index f03c05da0935b7f9b057f8f49fc62d97be49e7c2..68ea86c10d3c0a6e4940612b97626bc6a4010414 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -781,6 +781,11 @@ class CONTENT_EXPORT RenderWidget
   // Indicates whether this widget has focus.
   bool has_focus_;
 
+  // When selection exceeds the boundary, it should stay at the boundary.
+  std::pair<int, int> adjustSelectionForBoundary(int selectionStart,
+                                                 int selectionEnd,
+                                                 const int textLength) const;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };