Enable basic IME functionality under Ash on Windows

win8/metro_driver/ime/text_service.h

Index: win8/metro_driver/ime/text_service.h
diff --git a/win8/metro_driver/ime/text_service.h b/win8/metro_driver/ime/text_service.h
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+++ b/win8/metro_driver/ime/text_service.h
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+// Copyright (c) 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 WIN8_METRO_DRIVER_IME_TEXT_SERVICE_H_
+#define WIN8_METRO_DRIVER_IME_TEXT_SERVICE_H_
+
+#include <Windows.h>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace metro_viewer {
+struct CharacterBounds;
+}
+
+namespace metro_driver {
+
+class TextServiceDelegate;
+
+// An interface to manage a virtual text store with which an IME communicates.
+class TextService {
+ public:
+  virtual ~TextService() {}
+
+  // Cancels on-going composition. Does nothing if there is no composition.
+  virtual void CancelComposition() = 0;
+
+  // Updates document type with |input_scopes| and caret/composition position
+  // with |character_bounds|.  An empty |input_scopes| indicates that IMEs
+  // should be disabled until non-empty |input_scopes| is specified.
+  // Note: |input_scopes| is defined as std::vector<int32> here rather than
+  // std::vector<InputScope> because the wire format of IPC message
+  // MetroViewerHostMsg_ImeTextInputClientUpdated uses std::vector<int32> to
+  // avoid dependency on <InputScope.h> header.
+  virtual void OnDocumentChanged(
+      const std::vector<int32>& input_scopes,
+      const std::vector<metro_viewer::CharacterBounds>& character_bounds) = 0;
+
+  // Must be called whenever the attached window gains keyboard focus.
+  virtual void OnWindowActivated() = 0;
+};
+
+// Returns an instance of TextService that works together with
+// |text_store_delegate| as if it was an text area owned by |window_handle|.
+scoped_ptr<TextService>
+CreateTextService(TextServiceDelegate* delegate, HWND window_handle);
+
+}  // namespace metro_driver
+
+#endif  // WIN8_METRO_DRIVER_IME_TEXT_SERVICE_H_