Reviewed by Adele.
WebCore:
        Moving Frame{Mac}::respondToChangedSelection to Frame.cpp
        Added new EditorClient method to handle old bridge function
        
        * bridge/EditorClient.h:
           Added respondToChangedSelection to replace old bridge function
        * editing/Editor.cpp:
        (WebCore::Editor::respondToChangedSelection):
           Add client call to replace old bridge call from Frame::respondToChangedSelection
        * editing/SelectionController.cpp:
        (WebCore::SelectionController::setSelection):
           No longer directly call Editor as Frame::respondToChangedSelection
           makes the call
        * page/Frame.cpp:
        (WebCore::Frame::respondToChangedSelection):
           Moved from FrameMac, replaced bridge call with call to Editor
        * page/mac/FrameMac.mm:
           Moved respondToChangedSelection to Frame.cpp
        * page/mac/WebCoreFrameBridge.h:
           Removed respondToChangedSelection from bridge
        * page/qt/FrameQt.cpp:
           Remove stub method for respondToChangedSelection
WebKit:
        Moved respondToChangedSelection from FrameBridge to EditorClient

        * WebCoreSupport/WebEditorClient.h:
        * WebCoreSupport/WebEditorClient.mm:
        (WebEditorClient::respondToChangedSelection):
        * WebCoreSupport/WebFrameBridge.mm:
          Removed respondToChangedSelection from bridge
WebKitQt:
        Stub for EditorClientQt::respondToChangedSelection

        * WebCoreSupport/EditorClientQt.cpp:
        (WebCore::EditorClientQt::respondToChangedSelection):
        * WebCoreSupport/EditorClientQt.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@20108 268f45cc-cd09-0410-ab3c-d52691b4dbfc