Add InputMethodObserver support into InputMethodBase

ui/base/ime/input_method_ibus.h

Index: ui/base/ime/input_method_ibus.h
diff --git a/ui/base/ime/input_method_ibus.h b/ui/base/ime/input_method_ibus.h
index 1f0b1948220256a93b82c9e6c8f2aa0b6d9b53a9..b4aecde5b30a210abc951acce76ee089b473bc9a 100644
--- a/ui/base/ime/input_method_ibus.h
+++ b/ui/base/ime/input_method_ibus.h
@@ -47,7 +47,6 @@ class UI_EXPORT InputMethodIBus
   virtual void OnTextInputTypeChanged(const TextInputClient* client) OVERRIDE;
   virtual void OnCaretBoundsChanged(const TextInputClient* client) OVERRIDE;
   virtual void CancelComposition(const TextInputClient* client) OVERRIDE;
-  virtual void OnInputLocaleChanged() OVERRIDE;
   virtual std::string GetInputLocale() OVERRIDE;
   virtual base::i18n::TextDirection GetInputTextDirection() OVERRIDE;
   virtual bool IsActive() OVERRIDE;
@@ -139,6 +138,9 @@ class UI_EXPORT InputMethodIBus
                            uint32 ibus_keyval, uint32 ibus_keycode,
                            uint32 ibus_state, bool is_handled);
 
+  // Processes a caret bounds changed event.
+  void OnCaretBoundsChangedInternal(const TextInputClient* client);
+
   // All pending key events. Note: we do not own these object, we just save
   // pointers to these object so that we can abandon them when necessary.
   // They will be deleted in ProcessKeyEventDone().