Introduce RenderWidgetHostViewWinTest for Tsf handling

ui/base/win/tsf_bridge.h

 // Copyright (c) 2012 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_WIN_TSF_BRIDGE_H_
 #define UI_BASE_WIN_TSF_BRIDGE_H_
 
 #include <Windows.h>
 #include "base/basictypes.h"
 #include "ui/base/ui_export.h"
 
 namespace ui {
 class TextInputClient;
 
 // TsfBridge provides high level IME related operations on top of Text Services
 // Framework (TSF). TsfBridge is managed by TLS because TSF related stuff is
 // associated with each thread and not allowed to access across thread boundary.
 // To be consistent with IMM32 behavior, TsfBridge is shared in the same thread.
 // TsfBridge is used by the web content text inputting field, for example
 // DisableIME() should be called if a password field is focused.
 //
 // TsfBridge also manages connectivity between TsfTextStore which is the backend
 // of text inputting and current focused TextInputClient.
 //
 // All methods in this class must be used in UI thread.
-class TsfBridge {
+class UI_EXPORT TsfBridge {
  public:
   virtual ~TsfBridge();
 
   // Returns the thread local TsfBridge instance. Initialize() must be called
   // first. Do not cache this pointer and use it after TsfBridge Shutdown().
-  static UI_EXPORT TsfBridge* GetInstance();
+  static TsfBridge* GetInstance();
 
   // Sets the thread local instance. Must be called before any calls to
   // GetInstance().
-  static UI_EXPORT bool Initialize();
+  static bool Initialize();
+
+  // Injects an alternative TsfBridge such as MockTsfBridge for testing. The
+  // injected object should be released by the caller. This function returns
+  // previous TsfBridge pointer with ownership.
+  static TsfBridge* ReplaceForTesting(TsfBridge* bridge);
 
   // Destroys the thread local instance.
   virtual void Shutdown() = 0;
 
   // Enables the IME.
   // Returns false if an error occures.
   virtual bool EnableIME() = 0;
 
   // Diables the IME.
   // Returns false if an error occures.
@@ skipping 19 matching lines @@
   // Uses GetInstance() instead.
   TsfBridge();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TsfBridge);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_WIN_TSF_BRIDGE_H_