Introduce WebInputMethodController to blink

third_party/WebKit/public/web/WebFrameWidget.h

 /*
  * Copyright (C) 2014 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 20 matching lines @@
 #ifndef WebFrameWidget_h
 #define WebFrameWidget_h
 
 #include "../platform/WebCommon.h"
 #include "../platform/WebPageVisibilityState.h"
 #include "public/web/WebWidget.h"
 
 namespace blink {
 
 class WebLocalFrame;
+class WebInputMethodController;
 class WebView;
 class WebWidgetClient;
 
 class WebFrameWidget : public WebWidget {
 public:
     BLINK_EXPORT static WebFrameWidget* create(WebWidgetClient*, WebLocalFrame*);
     // Creates a frame widget for a WebView. Temporary helper to help transition
     // away from WebView inheriting WebWidget.
     // TODO(dcheng): Remove once transition is complete.
     BLINK_EXPORT static WebFrameWidget* create(WebWidgetClient*, WebView*, WebLocalFrame* mainFrame);
@@ skipping 17 matching lines @@
     // Setting this takes effect for the currently loaded page, if any, and
     // persists across subsequent navigations. Defaults to white prior to the
     // first call to this method.
     virtual void setBaseBackgroundColor(WebColor) = 0;
 
     // Returns the local root of this WebFrameWidget.
     virtual WebLocalFrame* localRoot() = 0;
 
     // WebWidget implementation.
     bool isWebFrameWidget() const final { return true; }
+
+    // Current instance of the active WebInputMethodController, that is, the
+    // WebInputMethodController corresponding to (and owned by) the focused
+    // WebLocalFrameImpl. It might return nullptr when there are no focused
+    // frames or possibly when the WebFrameWidget does not accept IME events.
+    virtual WebInputMethodController* getActiveWebInputMethodController() const = 0;

[EhsanK, 2016/09/14 18:55:27]

With this change, I would expect all the calls to WebWidget::foo()
which are related to IME be replaced with
WebWidget::getActiveWebInputMethodController()::foo().
But I have not made this change yet since this will make the CL much bigger. I
can do that here or later when we have implemented all the IME related code
inside the WebInputMethodControllerImpl class.

 };
 
 } // namespace blink
 
 #endif