Adds a test for setting empty composition text.

ui/base/ime/dummy_text_input_client.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_IME_DUMMY_TEXT_INPUT_CLIENT_H_
 #define UI_BASE_IME_DUMMY_TEXT_INPUT_CLIENT_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 34 matching lines @@
   void OnInputMethodChanged() override;
   bool ChangeTextDirectionAndLayoutAlignment(
       base::i18n::TextDirection direction) override;
   void ExtendSelectionAndDelete(size_t before, size_t after) override;
   void EnsureCaretNotInRect(const gfx::Rect& rect) override;
   bool IsTextEditCommandEnabled(TextEditCommand command) const override;
   void SetTextEditCommandForNextKeyEvent(TextEditCommand command) override;
 
   int insert_char_count() const { return insert_char_count_; }
   base::char16 last_insert_char() const { return last_insert_char_; }
-  int insert_text_count() const { return insert_text_count_; }
-  base::string16 last_insert_text() const { return last_insert_text_; }
-  int set_composition_count() const { return set_composition_count_; }
-  const CompositionText& last_composition() const { return last_composition_; }
+  const std::vector<base::string16>& insert_text_history() const {
+    return insert_text_history_;
+  }
+  const std::vector<CompositionText>& composition_history() const {
+    return composition_history_;
+  }
 
   TextInputType text_input_type_;
 
   DISALLOW_COPY_AND_ASSIGN(DummyTextInputClient);
 
  private:
   int insert_char_count_;
-  int insert_text_count_;
-  int set_composition_count_;
   base::char16 last_insert_char_;
-  base::string16 last_insert_text_;
-  CompositionText last_composition_;
+  std::vector<base::string16> insert_text_history_;
+  std::vector<CompositionText> composition_history_;
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_IME_DUMMY_TEXT_INPUT_CLIENT_H_