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 605b92ef67f443970001d930882b54f883883913..8008ff5b55017f009abe1cca221a5dcf3a3a69db 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -772,6 +772,11 @@ 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);
 };