Reviewed by Jian Li.

        [chromium]Remove deprecated code related to input method.
        https://bugs.webkit.org/show_bug.cgi?id=41244

        Also update TestWebWidget in tests/PopupMenuTest.cpp to add missing implementations.

        * WebKit.gyp:
        * public/WebCompositionCommand.h: Removed.
        * public/WebViewClient.h:
        * public/WebWidget.h:
        * src/EditorClientImpl.cpp:
        (WebKit::EditorClientImpl::setInputMethodState):
        * src/WebPopupMenuImpl.cpp:
        * src/WebPopupMenuImpl.h:
        * src/WebViewImpl.cpp:
        * src/WebViewImpl.h:
        * tests/PopupMenuTest.cpp:
        (WebKit::TestWebWidget::setComposition):
        (WebKit::TestWebWidget::confirmComposition):
        (WebKit::TestWebWidget::textInputType):
        (WebKit::TestWebWidget::caretOrSelectionBounds):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@62039 268f45cc-cd09-0410-ab3c-d52691b4dbfc