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

third_party/WebKit/Source/core/editing/InputMethodController.h

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 58 matching lines @@
     void cancelComposition();
     void cancelCompositionIfSelectionIsInvalid();
     EphemeralRange compositionEphemeralRange() const;
     Range* compositionRange() const;
 
     void clear();
     void documentDetached();
 
     PlainTextRange getSelectionOffsets() const;
     // Returns true if setting selection to specified offsets, otherwise false.
-    bool setEditableSelectionOffsets(const PlainTextRange&);
+    bool setEditableSelectionOffsets(int start, int end);

[yosin_UTC9, 2016/06/03 07:16:11]

Could you explain benefit of you replace |PlaintTextRange| by |start| and |end|
pair?
We use |PlaintTextRange| in |InputMethodController| in many places, I don't want
to have two representations of range.

     void extendSelectionAndDelete(int before, int after);
 
 private:
     class SelectionOffsetsScope {
         WTF_MAKE_NONCOPYABLE(SelectionOffsetsScope);
         STACK_ALLOCATED();
     public:
         explicit SelectionOffsetsScope(InputMethodController*);
         ~SelectionOffsetsScope();
     private:
@@ skipping 17 matching lines @@
     }
 
     String composingText() const;
     void selectComposition() const;
     bool setSelectionOffsets(const PlainTextRange&);
 };
 
 } // namespace blink
 
 #endif // InputMethodController_h